https://www.schwalbetires.com/tech_info/tire_dimensions -- scroll down for Schwalbe's tire / rim combo limits. Keep in mind this is coming from a tire maker who wants to sell you tire no matter your rim. Sheldon Brown's chart is much more conservative.
Going cheap, just ask in the classic & vintage section here. Or a local MTB FaceBook group. Most likely you can get a nearly free set of wheels from someone who is tired of tripping over them his garage. Last summer I picked up a set of 26in wheels and two set of tires with tubes, 8spd cassette included: $50 plus a 25 minute drive. They ended up being much nicer than I expected. They were from the 90s, but hardly used. (.... I also picked up a hardly used set a couple years ago and they were laced way toooo tight, and the side wall ended up splitting / failing after very little use. i ignored the warnings from the rear wheel when a couple of spokes broke...... caveat emptor).
As far as good, wide rims, I have been using a set of Cliff Hangers for a couple years. Going to be a $350 ~ $400 set of wheels. After much use and some mild abuse they remain true and round. I recommend them with 2 thumbs up.
https://www.velocityusa.com/product/...iff-hanger-559 - they offer a machined side wall.
My frame only clear a 2.3 in tire, which is what I used for a long & dirty bike tour this summer.
cheers.
