TechPowerUp compiled a nice chart of the 5700 and 5700XT cards they tested. Aftermarket cards do do a better job than AMD's reference cooler, but mid to upper 70s on the GPU under gaming loads isn't bad, much better than the 90s of the reference edition. Not really anything you can do to improve it except spin the fans faster.
Sadly that's a pretty common occurrence lately, design defects that hinder performance, probably the most widely known currently is the fact that 5G phones overheat so badly they drop to 4G, and don't work in ambient temperatures above 85F. But of course through the years there's a host of badly designed laptops which overheat and throttle (even the new expensive Surface Pro laptops), CPUs which ship with a cooler barely sufficient and cause it to throttle, GPUs which require manually setting the fans very high to keep them from throttling...Sadly bad/cheap engineering does not mean a product is defective.
In this case, however, it seems as if ASUS is citing AMD as the reason for their badly designed cards, as this seems to be their copy paste response to negative Newegg reviews about this very card. Also in their response they ask about which fan curve they are using, which goes to another well known issue that effective coolers for high wattage cards are loud as a heck unless they're properly designed and made with proper conductive materials, so manufacturers have been spinning the fans slowly until temps rise to near or at throttling speeds.
But it is one of the least expensive models, and there's a tradeoff that comes with cheapness, and that's usually undesired operation.
And on higher end products, those problems are reduced to non existent.
The REAL problem, however, is the fact that when someone buys one of these cards, which may be more expensive than the nVidia counterpart, and has a very negative experience, there's a high degree of likelihood that they will choose the competitor product the next time, or even return it and get the competitor product, in which case AMD lost a customer though the fault of a board partner, and it should be AMD's standard procedure to require all board partners to send them products to certify it meets certain standards and does not cause negative experience, press, and revenue loss due to faulty or cheap engineering.
According to this reply in General Discussion concerning the article I previously posted. Asus is using a Carbon Sheet instead of Thermal Paste which is why the vRAM doesn't overheat and get damaged: https://community.amd.com/thread/247082
according to the Youtube you linked, The reviewer mentions the sole cooling comes from the Air flow from the three fans on the GPU card.
From the Youtube link you posted it shows a heatsink for the vRAM:
So the Asus card does have a heatsink. may not be the most efficient but with the 3 fans blowing air looks like it is enough from causing the vRAM to overheat.
(1). Regarding the Asus TUF RX5700XT review.
No that is the point of the review. The heat spreader over the VRAM on that RX5700XT is NOT enough to prevent the VRAM Modules from overheating. They are hitting 104'C whilst the Spec for the VRAM on the PCB is max operating temp of 95'C.
I believe the whole AMD saying GPU Tjmax = 110'C is o.k. refers to the AMD GPU, not the VRAM on the PCB.
Both the Radeon VII and the RX5700XT introduced more thermal sensors on the GPU dies and those cards report more hotspot temps, not just an average GPU die edge temp which is used on older AMD GPUs.
(2). Regarding the new temperature sensors. It is detailed here:
AMD Radeon RX 5700 XT Review: Thermals, Noise, Gaming, & Broken Drivers - YouTube
The testing was done on an open air bench PC with Ambient temp of ~ 20-21'C.
Put that GPU in a PC case and you will easily get higher temps.in the PC Case.
(2). Regarding the ASUS TUF RX5700 review.
The issue is still the VRAM Cooling.
Those results were taken using an open air test bench again.
I have not determined what Ambient Temperature was for their testing.
Even if I make an assumption that it was 20-21'C, on an open air test bench, and assuming they report absolute temps: 
There is only 95'-84' = 11'C of thermal headroom below maximum operating temperature specification for the VRAM on the PCB in an open air test bench at an assumed 20-21'C (I will try again to find out what Ambient temps were but that's normally what is used).
So what happens when you put that GPU in a PC Case where Ambient is ~ 10'C higher?
You will be operating on the edge of or beyond the VRAM operating spec.
I do not think 11'C of thermal headroom is enough.
This is the evidence you need to send your GPU back, assuming I have the correct model and you can repeat these results:
Just click on this link for more explanation of VRAM temperatures in the review: Worst 5700 XT Period, Asus TUF Gaming X3 RX 5700 XT OC, DON'T BUY! - YouTube
The ASUS TUF Gaming X3 RX 5700 XT OC in that review is showing a GDDR6 Temperature of 104'C which is outside the maximum Operating Spec of the VRAM memory.
If you can repeat that test or show VRAM temps above 95'C in gaming or other tests then the card has a problem.
From the Creators of the YouTube that Black Zion linked: https://www.kitguru.net/components/graphic-cards/dominic-moass/asus-rx-5700-tuf-gaming-x3-oc-edition...
For our temperature testing, we measure the peak GPU core temperature under load, as well as the GPU temperature with the card idling on the desktop. A reading under load comes from running the 3DMark Fire Strike Ultra stress test for 30 minutes. An idle reading comes after leaving the system on the Windows desktop for 30 minutes.
Looking closer, however, we can see that all is not well. Above we have five RX 5700/5700 XT cards on their own chart, with those cards also including built-in memory temperature sensors where AMD reports the maximum temperature of the hottest memory module through Wattman (and GPU-Z).
As you can see, the TUF Gaming X3’s memory peaked a whole 10C hotter than the reference RX 5700. We mentioned at the start of this review how the lack of any kind of VRAM cooling was surprising, and it certainly shows based on this testing.
It’s not just that it runs hotter under load, but as we will see on the next page, the card isn’t as quiet as it could be due to the fact that the VRAM relies entirely on the fans’ airflow for cooling. That also means the fans don’t have a zero rpm mode, as otherwise there’d simply be no cooling for the memory chips.
To be clear, edge and junction temperatures are great, the heatsink and its 4 heatpipes are more than sufficient to cool the GPU core – it’s the memory which has been entirely neglected here. Do bear in mind though, that GPU temperatures will always be higher if there is no VRAM cooling, as the heatsink isn’t having to deal with the heat from the memory as well, so we would expect better GPU-only temperatures considering the lack of VRAM cooling.
Obviously if you stress test the Memory is going to get hotter than during normal computer use such as playing games such as the results your posted from Crystal.
According to Kitguru, the Asus GPU card has one of the best thermal performance equivalent to the Red Devil RX5700.
NOTE: The above Kitguru Review is a very detail review of the Asus RX5700.
