> while most rental options we found were much more CPU focused

Out of curiosity have you benchmarked it? I find that AWS "vCPUs" are significantly slower than a core (or even hyperthread) of a real CPU, and this constrains memory bandwidth too. A single bare-metal can often replace many EC2s.

Another thing to consider is the easy access of persistent NVME drives, something not possible on AWS. Yes you still need backups, but ideally you will only need those backups once a year or less. I've dealt with extremely complex and expensive solutions on AWS that could be trivially solved by just one persistent machine with NVME drives (+ a spare for redundancy). Having the data there persistently (at a cheap price per GB) means you avoid having to shuffle data around or can precompute derived data to speed up lookups at runtime.

If you're actually serious about exploring options to move your infra to bare-metal or hybrid feel free to reach out for a no-obligations call; email in my profile. It seems like you've already optimized it quite well so I'd be curious to see if there is still room for improvement. (Or if you don’t mind, share what your stack is and let others chip in too!)