Does Arch by chance have the new linux glibc that interferes with QWebEngine/chrome?
New glibc versions have added a clone3 call that disallows checking the chrome sandbox, which in turn causes qtwebengine process to crash.
Qt6 works around that call but older Qt 5.15 may not, and our official Qt 5.12.9 does not handle this case.
The workaround is to disabled qtwebengine built in sandboxing.
See:
https://www.mobileread.com/forums/sh...d.php?t=345988
https://chromium-review.googlesource.../src/+/2936184
https://bugs.launchpad.net/ubuntu/+s...c/+bug/1939993