It's a nice gesture but I'm a bit doubtful that there's enough people here to sustain a private tracker. Taking a guess at this but it seems most people here in c/piracy are general users, not specifically private tracker users - in fact a fair amount don't even like the idea of private trackers.
!trackers@lemmy.dbzer0.com exists but it's pretty quiet by comparison.
Not saying it's a bad idea but it could be a while before a niche tracker like that would gain enough traction to sustain itself. And I'm just talking about a regular private tracker, not even going to touch on the idea of someone developing a "decentralized private tracker" whatever that means.. TBH if you want decentralized just stick to public torrents with DHT/PEX, that's already decentralized. Or maybe make a semi-private tracker like Demonoid if that's more along the lines of what you want.
That doesn't sound like too many, you're saying you're at under 1000 torrents? How many multiples of hundreds are we talking?
Surprised Transmission has issues seeding that many, thought Transmission 4.x made improvements in that area. How much RAM does your system have? Maybe at some point you just need more system resources to handle the load.
PS - For what it's worth you can still stick with Transmission and/or other torrent clients & just spread the torrents among multiple torrent client instances. e.g. run multiple Transmission instances with each seeding 1000 or whatever amount of torrents works for you.