This is the alsa conf that LE12.2 uses, it is focussed on HDMI output and the 3.5mm Jack output is unlikely to work:
I am reworking audio support for LE13 to hopefully to get pass-through HDMI audio working. I might play with analogue later, but it's not a priority for LE users so not a priority for me either. I have no interest in trying to support other distros like Debian - which has a forum where you can ask for help from people that understand its packaging and requirements.
LE13 dev images support installation of browsers via flatpak. There are test images here: https://chewitt.libreelec.tv/testing/ although the latest ones posted have some major improvements for video decoding and I have not tested them on S905X3 (SM1) hardware yet. Testing is $free though.
In future posts please use line-breaks in your text instead of posting one huge wall of text.