FCPX Recent Projects are Never Remembered

Try resetting FCP preferences. Hold Option and Command while launching FCP and choose Delete Preferences. It will open the default Untitled library. Re-open the library you were working on, set the Preferences back to the way you like them (disable background rendering, reset Import to Leave Files in Place, etc.) and see if the issue has been resolved.

When you did a fresh FCPX install, you wiped out preferences, so those Recents were forgotten. Over time Recents will build back up.

If you've opened several Libraries already, that should be on connected and properly functioning drives, then yes, something is wrong, you should have recents showing up the minute to start opening Libraries, as they get opened and remembered as Recents.

Did you migrate your data from your old Mac to the new M3 Pro? If you did and migrated everything, including Applications and System Files, it's possible this is causing the issue because some older, incompatible software came along for the ride. The recommendation when moving to a new machine is to migrate *only* the user data, no Applications, no System files, nothing else. Then download fresh copies of your Apps from the App Store or 3rd party developer. It's more work but can make sure your Mac is running at its tip top performance. Especially if you went from an Intel machine to an M class.

If you think this might be the case, it's much easier to start over on the newer Macs. Here's a guide from Luis, long-time contributor and FCP sage:

Reinstall for Apple silicon Macs:

1) BACKUP - preferably two of them, as you are going to erase your content from the main drive

2) System Settings->General->Transfer or Reset, click Erase All Contents and Settings...

3) When your system restarts like if for the first time, and you are asked, choose to migrate "from another mac, drive or Time Machine backup" AND CRUCIALLY: check ONLY the user accounts

4) Yes it will take some time to reinstall stuff, but it's totally worth it. You will finally see how your new Mac is supposed to perform

Darn, I was hoping you'd say you migrated everything from an Intel Mac.

Create a new admin user, login as that user and create a few simple libraries with FCP. Are Recents still missing?

Either way, post an https://etrecheck.com report here using the Additional text button below in your reply. Maybe there's something that will jump out to the hive mind here.

Do other applications on your Mac remember recently opened documents? You're positive FCP is enabled in the Full Disk Access pane?