At this point, you're better of self-hosting, or even co-lo hosting. Cloud environments are good when you need to scale faster than servers can be shipped (or plan to scale down before the costs add up), but $5k a month is literally a new, decently-beefy server every 2-3 months.

In terms of solving the money issue, I feel like the only solution is a shared-cost/ shared-ownership model, where you get an initial pool of money together for the initial build-out, and then monthly costs are divided equally among all members. You can't rely on donations, you need collectivism.