SQLite is fine, but I have ran Postgresql on a $20 server without any issues, and I would suggest if you have to deal with concurrent users and tasks, Postgresql is the way to go. SQLite WAL works, but sometimes it caused some issues, when you have a lot of concurrent tasks running continuously.

And, not sure I'm correct, but I felt Postgresql has more optimized storage if you have large text data than SQLite, at least for me I had storage full with SQLite, but same application on Postgresql never had this issue