Serving users is one thing. Then you want to run some interactive analytics or cronjobs for cleanup etc on the db. Even if the load can manage it, how would the admin jobs connect to the database. I’ve never seen a db with only one client. There is always some auxiliary thing, even when you don’t consider yourself a microservice shop.
For analytics the solution is very simple. Just copy the database and run the queries on the copy.
agree - with SQLite and DuckDB I've really switched my mindset from one perfect, pristine DB to multiple copies and a medallion architecture that looks more like participation ribbons for everyone! The resources required are so cheap & lightweight when you avoid the big "BI focused" tech stacks.