Honestly amazing how well NewPipe works on the Librem 5 running via "Android Translation Layer". I had to turn down the resolution from the default 720p60fps to 240p for it to play videos reliably (didn't test anything between those) and the UI looks scuffed with various missing icons and such, but crucially it plays videos back more reliably than any other YouTube app I've tried on #postmarketOS!
On #Flathub if you want to try it yourself: https://flathub.org/apps/net.newpipe.NewPipe