Best solution for Backup/Time Machine Drive for Mac Mini late 2014

I have a Mac Min late 2014. I realise that the Thunderbolt port on it is 2 and not 3. The USB drive I was using for Time Machine has failed and I am looking for the best solution. Would another USB drive be the best way to go or would it be a good idea to make use of that Thunderbolt port. If so, what’s the best drive?

I have that machine and just used a USB 3 drive.

I have that now, but I was wondering if a T-Bird one would give me any advantages.

Only advantage to a TB drive old be for a clone. If internal drive fails the external TB SSD would be somewhat faster. If the external is a spinning drive then USB is the way to go. You won’t see any speed increase.