Welcome! And thanks for the report.
There are other problems with audio playback in Qt 6.11.1 which at least v100 uses (not sure about v99 at the moment): see this ongoing issue. We seem to have drilled down to Qt 6.11.x-without-ffmpeg-support being the culprit; either downgrading to Qt 6.10.x (with or without ffmpeg support) or compiling 6.11.1 with ffmpeg support fixes the problem mentioned there.
I’d appreciate if you could give the three debug builds listed in this table a try & report if and how they react for each build here in the forum, not in that issue. If the crashes persist, I’ll likely ask you to open a new issue over on Codeberg.