Not the Framework 16, but I've used the Framework 13 for 2 years now and have lived it with Ubuntu. I believe Fedora was also mentioned on the Linux support page back then, although I was just getting into Linux at that point so my memory could be wrong, but I'm pretty sure. I haven't used Fedora personally but I think it would be absolutely fine on the Framework 16.
They don't anymore unfortunately. The best solution I've seen is using winapps for Linux, but even that relies on a Windows VM. Worth looking into though still imo, it's how I use the latest version of Excel for my work.
PeerTube in general is the best alternative so far. TILvids is an example of a PeerTube instance, but PeerTube is federated just like Lemmy here, so you can find a different instance if you don't like TILvids, or even host your own if you want! I don't know the best instance for you off the top of my head though, I just use TILvids as well, which works fine for me as just a viewer.
You can in fact change the handler to NewPipe! Navigate in your settings to wherever your screen is that shows you a list of all your apps. Navigate to YouTube (assuming you have that installed, skip this step if you don't have it installed), and find the "Open by default" option (might be named differently depending on your Android provider), and disallow the option to open supported links. Now go back to your apps list and find whatever NewPipe application you use (I use the Sponsorblock fork for instance), click the "Open by default" option again, make sure it's enabled, then there should be a list of links supported. For the types of links you want supported, make sure they have a check box by it, and you should be good!
As a user of a Xperia One IV, I can say I've been very impressed and very happy with my phone. One of the few good phones that still has a headphone jack and a microsd card slot, both of which I regularly use. When it runs out of updates at some point, I can install a custom OS on it like Lineage, so it's been awesome and I'll be using this phone for years to come. If you can afford one (since they are quite expensive, I got mine on a sale and it was still expensive), I highly recommend it.
Not the Framework 16, but I've used the Framework 13 for 2 years now and have lived it with Ubuntu. I believe Fedora was also mentioned on the Linux support page back then, although I was just getting into Linux at that point so my memory could be wrong, but I'm pretty sure. I haven't used Fedora personally but I think it would be absolutely fine on the Framework 16.