Wondering if you've made any discoveries here. I finally upgraded a machine to Big Sur in spite of all the negative things I've heard (many of which look to be true so far) so I can test some software for a client who is also running Big Sur. It looks like the ODBC Manager (comes with Actual Technologies drivers) kinda works. It looks like iODBC also kinda works. I was able to get a DSN configured that will work with FileMaker 18 and 19, BUT now that I've configured it, neither of them will allow me to actually edit or change the DSN in any way. I can't even delete it and create a new one.