Depends on where you live, but here in Canada, PiShop (https://pishop.ca) usually has 4B kits in stock. I haven't seen single boards being available for a long time though.
Just make it hibernate after X time (2 hours for me). There a repo of scripts on github (https://github.com/lightrush/framework-laptop-formula) where you might find information on how to do it. I'm sure it's not a 1 to 1 port to Arch, but it might get you started. Just note I had to disable secure boot for hibernate to work.
I can vouch for the Framework. It doesn't feel beta at all. I'm running Xubuntu 21.10 on it an it rocks. Someone created a repo with salt scripts which works all the kinks of the laptop under Ubuntu. The only thing I needed it for was to fix the touchpad issue after resume from sleep (it would be at max acceleration) and to enable hibernate (just note that you must disable secure boot first). https://github.com/lightrush/framework-laptop-formula
Actually, it probably isn't that bad if it's well balanced. I own a Meta Quest 2 and I added an external battery at the back of the headstrap because it helps balancing the headset while playing, preventing it from dropping on my nose too much.
I see people have issues with the price tag, and while it is by no mean cheap, since it's actually a full blown computer AND a VR headset all in one, it is somewhat justified. The computer specs match my Framework laptop and the headset is, on paper, on par or better than other high-end VR headsets (and a miles ahead of my Meta Quest 2 and other consumer-grade VR headsets).
The stock headset definitely needs to be upgraded for this kind of application.
I own a BoboVR headband with an external battery, which helps balance the weight of the headset. I had the elite strap with external battery and the BoboVR is much more comfortable for me. It’s also leatherette instead of foam, so much easier to clean.
I also have a fan (BoboVR F2) attached to the face mask in order to prevent condensation and overall I get a great experience even when I drip of sweat after exercising.
I do pretty much the same thing. I own a Quest 2 and I play Pistol whip, Thrill of the fight and Moon rider (a free VR game which is played in the browser where you need to hit blocks with your hands synced to music).
The only issue I have with Thrill of the fight is that when I get into it, I hit hard, but find no resistance as I would hitting a punching bad or sparring with someone, so my elbow tends to overextend and I feel some pain for a couple days after playing for about 30 minutes. That’s something that will probably get better over time as I gain more control, but as of now, that’s something I need to be careful of.
I'm running Xubuntu on mine and it works fine. Battery life goes down pretty quick when sleeping, and battery life is definitely lower than Windows, but I can still get 4-5 hours of actual work on it.
I used to own a BB Z30, which I bought after my q10 developer édition began having issues, and to this day I still think this is the best phone I ever used, primarily because of the BB OS. I had only owned iPhones before that and have owned both Android and iPhones since then.