Need Advice - Boot Drive Options for 10th Gen Intel NUC

Hello

I have 4x 10th gen intel nucs, the tall version.

They are running proxmox, booting from a sandisk usb flash drive. Worked for months without issues. I moved recently and went to turn them back on after being off for a few months. 2 of them are fine, the other 2 wont boot from usb anymore, even though the drive is recognizable. I figured this would happen due to all of the warning regarding using usb drives to boot.

Are there any usb drives that I can buy as a replacement that are more reliable? Something that wont break if you look at them wrong...

Should I buy 4x 32gb internal ssd and install proxmox to those instead of the usb?

A part of me realizes these nucs are old, and dont support 2.5gbe networklng, so maybe replacing the 4 with 2 newer nucs is a better move? Less power, less hosts to manage... They are perfectly fine for what I use them for, and I hate to waste 4 of them... Just dont want to keep sinking money into them if they themselves may give out soon.

What would you do if you were in my shoes?? I am willing to rebuild everything and I am not necessarily looking to recover anything. However, if I can buy good usb drives, reinstall proxmox, and then have the new instance rediscover what was installed on the internal m2 ssd, then that is probably the path of least resistance.

What do you think?