When I hear numbers like this I wonder what percentage of the compute and memory resources of that 18-32 node cluster — not to mention the engineering that went into making it work — goes into the “hard” problems of horizontal scaling, cramming stateful services into an architecture designed for stateless ones, etc.

You can actually get a couple of pretty beefy bare metal boxes for that budget. Or a couple of more modest ones for app servers plus a nice big RDS instance with all the trimmings. Based on past experience, that’ll get you to a few hundred rps for even a fairly complicated, poorly-tuned Rails or PHP app; your well-factored Go API server should handle 10x that pretty easily.

You might have to write some Bash or systemd unit files instead of a bunch of YAML, which may or may not bug you. I find shell easier to understand and debug than YAML-based scripting but YMMV.