I’ve reinstalled DxO OpticsPro version 8 up to PhotoLab v4 on my MacBook Air M1 (8core GPU, 16GB Ram, 1TB drive). This is what I got:
OpticsPro 8: does not run
OpticsPro 9 and 10 : run with some quirks (e.g. presets not shown in the tool)
OpticsPro 11: seems to run as expected
PhotoLab 1: Installed after a few quirks and seems to run as expected
PhotoLab 2 and up: seem to run as expected
Please note that I did not test the old apps thoroughly. Nevertheless, I got no crashes with any of the apps except for OP8. This means that the apps themselves are fairly tolerant, even when there is no official support any more.