Ran into the same thing. SQLite works until you need cold start recovery or WAL contention with concurrent agents. Built a dedicated memory layer for agent workloads - happy to share: https://github.com/RYJOX-Technologies/Synrix-Memory-Engine
The project is here: https://codeberg.org/ZelphirKaltstahl/web-app-vocabulary-tra... But I left it unfinished and a quick grep does not yield comments or something that explains why at some place I do something to circumvent the SQLite problems. I remember though, that I basically swore to myself, that I would not ever use SQLite in production with Django ORM. And if I am not using it in production, then testing also better should not be using it, because one should test with the same RDBMS as runs in production, or risk unexpected issues suddenly only happening in production. So SQLite is out for anything serious in Django projects for me.