First things first: I did change "bootstrap-2@3_11_6_chromium_30_bin\python3\bin" to ".cipd_bin\3.8\bin" in "depot_tools\python3_bin_reldir.txt"
Does not work anymore, the content of reldir is not respected anymore (using 3.11 instead of my 3.8 in reldir) . As I am not aware of the concepts of the build system I hard-coded the python path in python3.bat of depot_tools dir, and it is now compiling again with python 3.8.
I guess in upcoming branches this will be fixed anyways, but just in case someone else stumbles