Without monetisation of this product, even when you scale up to many streamers, eventually you’ll start burning money.
So, this product/use case lends itself to to being “self hosted” and thus the user wanting it would provide their own ClientID/Secret, which then negates the problem of the rate limit. Since people would run their own instance with their own keys.
You’ll only get so far on your “master key set”. And/or spare server capacity/free cloud usage tiers.
Eventually you are either losing money or your hit the limit of subscriptions. So the ultimate fix, is people provide their own keys either to a self hosted copy, or to you, but of course, people shouldn’t be distributing their client secret…
So, even if you have infinite topics, you still have the “server cost” problem eventually. Or even, the Discord Rate limit problem. Depending on how much you are sending where.