See Windows 7 builds (both HEDT and consumer desktop).
Note: There's no officially supported AMD HEDT build for Win8, because the first HEDT from AMD is the Threadripper, which officially only supports Windows 10 and up. For unofficially supported builds, see Windows 7 builds.
Even the first generation of AM4 chipsets, A320/B350/X370, only supports Windows 7/10/11. The last high-end CPU before that generation happens to be the same as the last that supports XP, as AMD didn't make high-end desktop CPUs at all between 2013 and 2016.
The RTX 2080 Ti is between the R9 295 X2 and the RX 6950 XT in performance.
On the driver search page, the last generation that Nvidia advertised Windows 8.x compatiblity for is the GeForce 10 Series. However, the Windows 7 driver actually contains lines in the INF files for the 16 and 20 series of cards, so these cards should be supported without any driver modifications. The 30 series (and TITAN V, CMP 90HX, CMP 70HX) is only listed for Windows 7 and not 8.x though, and adding the lines to the INF files is still not enough to make it work, according to an MSFN thread.
A patched driver for GeForce RTX 30 series (best: 3090 Ti) is available.
According to the release notes, AMD Radeon™ R9 Fury, Radeon™ Pro Duo and Radeon™ RX 400 Series are only supported by Radeon Software Crimson ReLive Edition on Windows 7/8.1/10 64-bit. AMD Radeon™ RX 500 Series graphics are only supported by Radeon Software Crimson ReLive Edition on Windows 7/10 64-bit.
However, the last Windows 7 driver for RX 6950 XT has lines for Windows 8.1 in its inf files. A Reddit post suggests that it might not actually be compatible though.