Try the other options I provided, rather than doom the card outright. See if it's not the TV's audio decoder. You said you tried headsets not a 2.5mm jack into the TV's headset jack, an entirely different thing. Are you using an A/V receiver or directly using the HDMI to the TV and those default speakers? Have you gotten the same crackling using the HDMI connected to some other audio output?
If the audio part of the card were bad, the other elements would be affected as well. It takes troubleshooting rather than a blanket "this is the problem" solution. There's multiple threads on many subjects on here about the same subjects and not one thread is the answer for all.
I can tell you for a fact the RX 5600 XT does not have a common audio failure that I know of. The driver for the audio is the same since 4/2020. Now different versions of the video driver have produced HDMI audio problems on certain cards, so if you're running 20.8.3 you shouldn't have any. 20.4.2, while the oldest is the first stable release that had virtually no issues other than some game support.
The fact you claim this problem started all of a sudden with no changes, means you'll need to troubleshoot the actual cause or try going through every thread that tells you what you want to hear, rather than troubleshooting the right solution.
So work like a flow chart. If you want to skip RAM testing or CPU settings/temps or even excessive dust, than eliminate the TV as an issue in any way shape or form, first. Try different cables/ports. Test the HDMI on another audio output, while using an alternate port for the display. Swap the card into another PC and see if it happens as a last resort.
Then you can be probably the first person to say the card's audio is bad while the rest of it works fine. Except you still skipped the RAM test at that point. The one part that works hand in hand with the GPU's slot and is known to cause this very issue. One error is a bad stick or setting and may not reproduce on the motherboard audio channel because it has it's own DAC and skips the PCIe lane that the GPU uses, where the HDMI is located. In fact anything else you have connected to a PCIe slot or even a defective USB device can cause this as well. RGB fans or lights, there's a lot to eliminate before just saying it's the card.
We can't test hardware for you. Skipping troubleshooting steps will lead to frustration at the least. Assume nothing and you will find the issue. Could be as simple as the TV's audio processor or if you use an A/V receiver, some problem with it or the connection to it. The fact you said you've read some threads tells me it's probably pretty simple if you apply the time.
"It worked before you broke it!"
