Both apk’s downloaded from official and reliable sources (Mozilla servers and F-Droid). In settings, the “Allow untrusted software” is enabled. Both packages install, and the browser launches, but there is no internet connection nor internet data traffic going on, none whatsoever.
The F-Droid store installed from Jolla Store also does not have internet connection, so it does not help trying to install Fennec from there.
Download sources of apk’s:
https://ftp.mozilla.org/pub/fenix/releases/132.0/android/fenix-132.0-android-arm64-v8a/