Yes, DxO have horrible OS support. Graphic design, music and video editors mostly do better to stay two versions behind for stability, if not three or four, as well as legacy plugins. DxO is running at the least the Mac world on current -1 or best case current -2.
I almost gave up on PhotoLab when DxO dropped support for Mojave (last official OS for Mac Pros, which I had fitted out with Radeon VII) with PhotoLab 5. If I didn’t regularly shoot very high ISO sets and like the app so much I would have.
DxO does not respect our investments or the pro workflow (which means not running the latest OS, latest OS is for tech reviewers, not artists, musicians and photographers).