How to recover files from USB drive for free?

I'm hoping someone here can help me out. I recently plugged in my SanDisk 512GB Ultra USB 3.0 Flash Drive on my Windows 11 PC, and to my surprise, dozens of photos that were stored on it have suddenly gone missing.

I’m not sure what happened. One day the photos were there, and the next day they were just... gone. I’ve searched the drive thoroughly and tried different computers, but no luck. It’s like the files vanished without a trace. Are there any free tools or methods that can help me recover the lost files from this USB drive? Thank you! (I had previously used this USB as a bootable drive a while ago, but later reformatted it and started using it to store personal files)