Jeff Geerling ran some benchmarks on USB storage options in 2020, including a pen drive SSD: https://www.jeffgeerling.com/blog/2020/fastest-usb-storage-options-raspberry-pi
Jeff Geerling ran some benchmarks on USB storage options in 2020, including a pen drive SSD: https://www.jeffgeerling.com/blog/2020/fastest-usb-storage-options-raspberry-pi
I also use those, but (shame on me) I've never tested the backups. Have you ever restored such an image backup?