A family of Microsoft relational database management systems designed for ease of use.
It isn't a Windows 10 vs 11 thing. It isn't a form vs subform thing.
It is an update that caused this issue. The solution, as explain in the link I provided earlier, is to either rollback your Office build or, simply create a trusted folder for both your front-end and back-end folders (you'll also have to delete orphaned msaccess.exe processes and ldb/laccdb lock files).