The YouTube TV (aka YouTube Leanback) (https://youtube.com/tv) interface is perfect to use on a HTPC / gaming PC build but we need to do some steps to unlock its full potential. YouTube will redirect you to the normal YouTube app if it detects your user agent is a normal, desktop one.

This will launch a Chromium-based browser in kiosk mode. Use a desktop file like this one, no need to install some separate Electron app or something. Ideally, use another web browser from the one you regularly use, or launch with a separate browser profile, something like --profile-directory="Profile 2".

~/.local/share/applications/YouTube.desktop

[Desktop Entry]
Type=Application
Name=YouTube
Exec=vivaldi --disable-vivaldi --kiosk --new-window --no-sandbox --user-agent="Mozilla/5.0 (PS4; Leanback Shell) Gecko/20100101 Firefox/65.0 LeanbackShell/01.00.01.75 Sony PS4/ (PS4, , no, CH)" https://youtube.com/tv

It should be more or less the same thing with Firefox and any other modern browser.

There's a lot of user agent switcher extensions like this one. Most of them lets you configure a user agent per website or domain, however if you set youtube.com/tv as homepage, or it otherwise loads on start, the page may load before the extension had time to load and so you end up with YouTube redirecting you to the main page anyway.

• Mozilla/5.0 (PS4; Leanback Shell) Gecko/20100101 Firefox/65.0 LeanbackShell/01.00.01.75 Sony PS4/ (PS4, , no, CH)¹⁾