All of this work and complete dependency on third party services is worth it? Isn't much easier to create a lightweight app in say, Go and SQLite, and pay a so-low-to-be-insignificant monthly fee?
Thinking about it, a holistic solution to this kind of problem would [categorically need to] be extremely expensive in order to ratelimit demand. Because it's not just "host this for me for a while" with an implicit sort of "maybe let it fall over one day and see if I yell at you" - that 2nd bit is completely removed, and the expectation is 100.0% (amortized, aggregate) uptime... indefinitely.
It's interesting how not even graves last forever. They decay over time (hundreds of years). Not all are maintained.
What sort of "forever" are you talking about? "Most Important Thing™ when the paperclip maximisers take over"?
In reality, it would probably be more effective to dedicate nearly $0 to infrastructure and $N,000.00 to an endowment for 1-3 hours of engineering time each year.
Figuring out how to host a static site for free and moving the site to that service requires almost no time for a competent engineer. But finding a solution that is guaranteed to exist in 100 years with zero human intervention would probably cost millions...