Q4os with Trinity desktop really needs little RAM and runs fast even on old devices. The desktop is a bit old-fashioned, but ok. You may also try lighter browsers, perhaps Palemoon.

But 4GB is actually not that little, almost all distros can run well with it, especially rather slim ones like Debian lxqt. maybe it’s really due to the hdd.

The development of UAD has been stopped/paused. The fork Universal Android Debloater Next Generation continues it

You can also download video or audio from some Individious instances. For desktop, Freetube is also recommended as a programme that can also do this and you can also subscribe to channels etc. via it. For others, perhaps interesting: for Android, NewPipe is highly recommended.