Hello friends, I am convinced that playing videos from a browser is disappointing, it plays with poor resolution and is very slow, my query is, how to install SMTUBE, an application to play YouTube videos, please can you tell me the steps ... many Thanks in advance.

I dunno, I use youtube-dl, which seems quite well supported by lots of other things nowadays.  In fact mpv even uses it to fetch content, you can simply do `mpv URL` and it will start playing.  It's much more lightweight than the web interface, as you already noticed.  Many other tools and interfaces leveraging it as well.