Hi Jess
You did run these commands and still have Django 4.x and cffi 1.15.x installed? As far as I know Seafile does not run (yet) with Django 4, so you need to downgrade to the 3.2.14 Version of Django. And check that you really have installed the cffi version mentioned above (1.14.6). I don’t know exactly if there is maybe a more recent version of cffi available (and supported by Seafile).
Here you can see the requirement for Django on the Announcement for Seafile 9.0.7: Seafile community edition 9.0.7 is ready! - Announcement - Seafile Community Forum
I am pretty sure with a downgrade of those versions it will work again.