So it seems like what is needed is a better host for XGBoost models instead of having to install, maintain and launch an entire database? Or am I missing something here?
Basically, postgresql is a stateful service, and stateful services are always major pain to manage -- you need to back them up, migrate, think about scaling... Sometimes they are inevitable, but that does not seem to be the case here.
If you have CI/CD set up, and do frequent deploys, it will be much easier and more reproducible to include models in build artifact and have them loaded from filesystem along with the rest of the code.