https://bugs.winehq.org/show_bug.cgi?id=54994
--- Comment #5 from C. Leu kle@bluewin.ch --- Okay folks, it is confirmed meanwhile that this problem here is a 100% Mesa one.
There exist also already an MR which will fix this "GLXBadFBConfig" problem: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23762
The mentioned workaround via a GL override like "MESA_GL_VERSION_OVERRIDE=4.6" seems to work in my case with the dolphin emulator. But it is also confirmed for example regarding Lutris that this tweak results in a black screen. Ergo, it is in general not a good idea to override the GL version because it might introduce other problems. ;-)
Maybe I should close this bug report here. Will do that when Mesa MR 23762 has landed.