Thank you for posting.
This morning Feb 1, 2022 with MSAccess Office 365 current channel 32 bit Version 2201 Build 16.0.14827.20028 click to run I started getting ""Cannot open any more databases error 3048." on a not too simple but had worked-fine-before form.
I noticed that when I finally was able to exit the debugger and quit my app and quit access that a lock file was still present which I could not delete, Task Manager showed a ghost MSAccess process running. I can kill the process, delete the lock file but they are just left again next time I run access.
I changed out a few small read-only subforms to using snapshots instead of dynasets and that seemed to delay the 3048 error messages until I'd scrolled further down the rows in browse mode but I still got the error.
The ghost process and lock files are still left behind even when I don't browse enough to get a 3048 error. I can open the app without the startup form and close it and then no ghost process or lock file but if I so much as open my startup form when I exit the ghost process and lock file is left behind.