The player with a "MSI Radeon 6800XT Gaming X Trio" is using "whql 21.4.1" drivers.
While the one with a 5700xt is using "v20.9.2" drivers.
For theses players, the in-game "lightmap compute" feature become almost unusable since compute takes ridiculously long time: 30mn to an hour instead of around 2-3 minutes.
We did not patch the 2 games for many years, and didn't notice that issue since now, so I assume something is going wrong on driver side.
Regards