It really is, its what i do. To enable developer mode you need to make an lg developer account and install the developer mode app from the lg app store. Once youve enabled that you can use this on your pc to install the yt adfree app. Its recommended to uninstall the old yt app first so if your tv lets you, do that. My tv doesent let me but the adfree app still works, it just gets uninstalled after you turn your tv off. You can install the homebrew channel from the same app which lets you install yt adfree without the tool after the first time. The app also has sponsorblock built in with customizable settings, its the best way to watch yt imo
Also note: after a few days dev mode seems to turn off, making all the apps disappear. You can just log back in and they should all reappear.
It's possible to auto-renew dev mode via SSH with a shell script running on an interval on another device in the network. I would give more detailed advice, but unfortunately it seems LG has changed that part of their API a while ago. The webOS manager linked above used to be able to generate a script for this purpose. I'm not sure if it still works, but it's worth checking out.
Interesting, ill for sure look into it and reply here if i figure it out. The dev manager linked DOES do something to the timer, my dev app shows 999 hours remaining however it still logs out after a few days. I dont use my tv everyday so maybe that has something to do with it?
The docs do imply this but I've had Jellyfin sideloaded via developer mode for a few weeks and I've never had to renew anything. It may have changed recently. This is on a C8.