GFork

This one can make you switch from Desktop UI to Mobile UI and vice versa.

By default, PC environment is "Force Youtube Desktop" and you are not allowed to visit "m.youtube.com"

Here you can have two options: Switch to another UI temporary, or switch to another UI persistently.

I would recommend you try the normal switching first.

Remember, if you switch to Mobile UI persistently, you are not allowed to go back Dekstop UI if you do not switch back to Desktop UI persistently.