I'm using a 500g Samsung T7. A lot of people suggest the T5, but I didn't really see any new ones listed on Amazon so went with the T7. It seems to work well. I'm also waiting for the Jeda USB Hub to be delivered which will give me more USB outlets while having the hard drive plugged in.
Agree with the T7. I formatted to ExFAT and the car recognized it and set everything up. The original format to FAT32, gave an error message saying the dashcam wouldnt work due to too many partitions.
Also waiting for the Jeda hub!