Hi Chris,
This is going to be a radical change and you may not want it. You do not "Import" into Bridge, rather you just view files. Bridge is a great viewer mind you but it serves different functions than LR does.
A number of years ago I wrote a 3-part introduction of Bridge. It's outdated in a number of ways at this point but enough of it is "good enough" to get you going. It's here:
https://community.adobe.com/t5/adobe-community-professionals/bridge-part-1-making-bridge-work-for-you-customizing-the-interface/td-p/4785280?page=1
https://community.adobe.com/t5/adobe-community-professionals/bridge-part-2-working-in-bridge/m-p/4785278?page=1#M18
https://community.adobe.com/t5/adobe-community-professionals/bridge-part-3-finding-your-images-in-adobe-bridge/td-p/4785282?page=1
The one big thing I do need to warn you about though is that ALL of your corrections, adjustments, etc. are probably all gone as all that is/was contained in LRC's Catalog which you state is no longer viable. One question on this: did you ever make backups? If so, those should be around somewhere and if you have one of them you can see if that's still viable.
Now mind you, since you are using an M1 Mini, the version of LR you used to have will not work on that at all. Another thing whether you're working on LRC or Bridge, you need to give permissions to access images on an external drive or even your Desktop. Follow the following instructions (Note: these are referring to Bridge but the same issues need to be done for any other application on your computer. And all this is from the MAC OS and does not have anything to do with the Mac Mini.:
Go to your System Preferences and select Security and Privacy (found in the top section). Now click on the Privacy setting (last tab). Now click on the lock on the bottom left and provide your Administrator code. Now select the Full Disk Access option and click on the "+" symbol. This will bring up the standard Mac Open window and let you add any application you want or need to have full access. Look for Bridge, select it, it will now appear in that window and make sure it's checked. Next go to the Files and Folders option and do the same thing as above (although there's nothing to check, just add. Close everything down and see if that makes it all work.
Please let me know
[Note: these images are from an older OS, the process is the same.]

