Selfhosted

If you're only at 10mbps upload you'll have to be very careful about selecting microsized 1080p (~4-9mbps) or quality 720p (~6-9mbps) encodes, and even then I really wouldn't bother. If you're not able to get any more upload speed from your plan then you'll either have to cancel the idea or host everything from a VPS.

You can go with a VPS and maybe make people chip in for the storage space, but in that case I'd still lean towards either microsized 1080p encodes or 1080p WEB-DL (which are inherently efficient for the size) if you want to have a big content base without breaking the bank. E.g, these prices look pretty doable if you've got people that can chip in: https://hostingby.design/app-hosting/. I'm not very familiar with what VPS options are available or reputable so you'll have to shop around. Anything with a big harddrive should pretty much work, though I'd probably recommend at least a few gigs of RAM just for Jellyfin (my long-running local instance is taking 1.3GB at the moment; no idea what the usual range might be). Also, you likely won't be able to transcode video, so you'll have to be a little careful about what everyone's playback devices support.

Edit: Also, if you're not familiar with microsized encodes, look for groups like BHDStudio, NAN0, hallowed, TAoE, QxR, HONE, PxHD, and such. I know at least BHDStudio, NAN0, and hallowed are well-regarded, but intentionally microsizing for streaming is a relatively new concept, and it's hard to sleuth out who's doing a good job and who's just crushing the hell out of the source and making a mess - especially because a lot of these groups don't even post source<->encode comparisons (I can guess why). You can find a lot of them on TL, ATH, and HUNO, if those acronyms mean anything to you. Otherwise, a lot of these groups post completely publicly as well, since most private trackers do not allow microsizing.