Don't forget NewPipe for Android, Yattee for Apple devices, SmartTube for most Android TV boxes, Playlet for Roku, and Invidious for PC (if you don't like Piped).
The only (usable) platform I can think of without a ad-free YouTube client is maybe webOS for LG TVs.
(some of these clients are also missing some features because they are new, but they should all be better for watching than the official app)
I don't comment at all, so NewPipe gets most of the functionaloty I would ever want from YouTube. Plus, it also helps by not having personalized reccomendations to keep me stuck watching it.
I've been enjoying my Pixel 5a as of late, but I would switch in a heartbeat if another OEM offered a product that's better for me. Brand loyalty doesn't make that much sense in my opinion, what does is looking for the best product for you.
ViMusic and InnerTune are both available on F-Droid, and are both YouTube Music clients (with reccomendations!). ViMusic is more established, but InnerTune seems to be more up-to-date.
Probably schools, those bad boys are pretty much designed to be used in schools. They are easy for the sysadmin to manage and they are easy to use for the student. They charge fast and stay charged for a long time, and most things a student would need can be found online. They also make it harder for a student to brick their own computer or do things they shouldn't. Even if they are horribly Google-ridden, they do work well in schools.
Chromebooks are nearly perfect student devices, especially newer ones.
They charge quickly, have long battery lives, and most things students would need are easily accessible on Chrome. As well, it's a little bit harder for students to exploit and put their own apps on in my experience, because it requires more knowledge than what most students have to counter things like social media blocks (Games are kinda an exception though).
While they probably aren't the best for other forms of usage, they are very good school devices. I wouldn't even consider using Macs or Windows laptops at schools instead.
NewPipe is great, it gets around the main issue with Piped/Invidious instances (that being rate limiting by Google). I've been using it for years and it's been great all this time.
Stremio + Torrentio + Real-Debrid is becoming better by the day now. I never had a Netflix subscription in the first place, but I don't think I would ever get one now.
There is Plexus which does this, I think they have an app now which could have more recent data than the website that you could get off of F-Droid (but I'd rather just use the website anyway).
Rootkits still can exist for Linux, but because there are more Windows users and thus more to be gained from a Windows virus of any sort, it would be pretty hard to find a rootkit for Linux.
It seems apps like SpotiFlyer and Spotube both use the Spotify discovery API but actually get the music from YT Music (which is already easy to download using yt-dlp, NewPipe, or another app of your choice). Kinda sad that I can't find a way to pirate music off of Spotify yet, but YT Music is pretty good for my purposes.
I would say for Linux to ust use uBO+FF and to not blindly copy terminal commands from the internet or to run random files with root. As many other comments have said there's clamAV to scan for Windows viruses but since Linux is far less prone to viruses (due to Linux viruses being quite uncommon), I think you're good without one.
Don't forget NewPipe for Android, Yattee for Apple devices, SmartTube for most Android TV boxes, Playlet for Roku, and Invidious for PC (if you don't like Piped).
The only (usable) platform I can think of without a ad-free YouTube client is maybe webOS for LG TVs.
(some of these clients are also missing some features because they are new, but they should all be better for watching than the official app)