I think of “thumb drives” as portable flash storage + USB. “Portable backup drives” have taken its place for me. Incredibly fast (NVMe + USB-C), quite small (M2 card size + case), durable (same as thumb drives), growing sizes (1-2 TB affordable).
I keep my old flash drives for smaller things like bootable apps, fresh OS installs, firmware updates. I definitely have no need for mystery off-brand storage though.