> A good framework can maybe cache some of this with the opcode cache, and apcu. Saving some milliseconds.

This framing is confusing because OPcache has for the past 15 years taken care of exactly this bootstrapping you're worried about. In a competing share-nothing setup you merely come in at a tie for performance (barring first run of `require`). I do not see 10-50ms latencies in any of my deploys which is why I'm skeptical.

That said, the big sell of your project for me might be memory management - less memory means more workers which is always a good thing if it comes at no cost to latency.