In December both the GA and the HWE kernels where on the same 5.4 version, so that was a different issue then. Some reported it working with an older 5.4 then and others with 5.8
A few AMD updates later it seems they work with 5.4 but not 5.8, and the latest post now is for a problem in 18.04 with 5.4, so also not with the 20.04 HWE now being on 5.8
So different problems are in that thread, and going with GA with is on 5.4 now, instead of HWE which is now on 5.8 works for their newest driver now, but would have made no difference in December. It was around 3 weeks ago that the HWE kernel was upgraded.
There seems to be quite a lot of confusion regarding the GA and HWE kernels and the point releases in that thread, especially from the AMD representative.
The hwe-edge kernel had 5.8 already since October in 20.04, so there was plenty of time to test for AMD and users, and some users reported there they had problems with it on 20.10 which uses 5.8.
Also that they claim that they got surprised when packages in the repositories where updated before the new installer was released when it always was done that way.
But I do think that Ubuntu can do better explaining and announcing the point release and everything that goes around it.
Maybe split the release notes up, in 2 or more phases, so that when the HWE kernel, mesa and xorg get updated as usual before the point release, maybe already when the packages are in proposed.
Then fewer people might get surprised and fewer think that 20.04.1, 20.04.2 are somehow different releases using different repositories requiring a distribution upgrade.
Then when the new installer is released announce that with a link to the previous announcement.
And that the updated kernels are already available for those that already have Ubuntu installed, and a extra chapter with all the other upgrades explaining that those updates also have been available for a while.
So a main focus about the new installer when the installer releases, and not put that together with all the other updates that have been made available already.