If your other monitor Samsung worked correctly with Freesync on and this new Samsung Monitor doesn't. It seems like it is a problem with the Monitor more than the AMD driver.
Your new Samsung Model is really about 3 years old according to the Driver and software download section of Samsung Support.
I noticed you enable Ultimate Engine Freesync instead of Standard Freesync. It is possible that Ultimate Engine is not compatible with your new Monitor. Try using Standard Freesync and see if it boots correctly.
Also check the Monitor's settings to see what is has for Freesync and see if you have the latest Samsung Monitor driver installed.
From your Samsung Manual concerning Freesync:
Ultimate engine or standard engine for FreeSync produces the same outcome. I know this is a 3 years old monitor, so was my Samsung CF390, they were out around the same time, CFG70 is the higher tier curved monitor with Quantum Dot and 144 refresh rate support. although I don't utilize the feature offered by the latter.
So naturally, I assume it will work without hassle, since CFG70 is supposed to be higher tier monitor than my old Samsung CF390, which I also used Freesync ultimate engine on. And apparently I was wrong. Dead wrong.
Found this AMD site that lists all Freesync Monitors. May not be up to date but I believe both of your models are listed: https://www.amd.com/en/products/freesync-monitors
There is no LC24F390 but there is C24F390FHC also there are two Models but one has C27FG70 the other is LC27FG70FG but both have similar Freesync in the matter both Freesync only works on Display Port outputs. The other monitor you had Freesync worked both on Display Port and HDMI
See if connecting your new Samsung to Display Port you are able to see BIOS when it boots up.
Also try installing a previous AMD Driver in case it is a problem with the latest version unless the other Monitor works with the current driver.
You can download a previous driver (~6 mos) from here: https://www.amd.com/en/support/previous-drivers/graphics/radeon-400-series/radeon-rx-400-series/rade...
Might also be worth trying to toggle CSM (compatibility support mode) on/off in the BIOS, and to put the monitor OSD panel back to default settings. I suspect the BIOS is using a resolution which the monitor perhaps does not support and that causes the black screen. Try toggling the various options in the monitor OSD to see if any of them helps to produce a display in the BIOS.
FreeSync will not be active in the BIOS, so for now you may just have to toggle it off via the OSD if you venture into the BIOS for now.