The Mavic 3 has been around long enough that it's possible you have a couple old (but new) batteries that haven't been properly maintained and have failed.
I have the Mini 3 (non pro) and the mini 4 pro. The mini's are awesome little drones but will always be limited by their size. I honestly see no need for a mini 5, if you want improvements over the mini4 pro go bigger. My Mavic 3 is still my...