USB can be problematic:
Some hardware RAID enclosure’s JBOD mode are not true direct access to disks. See above resource for potential problems.
That is nice, and if it worked with TrueNAS, great. But, that is not the only problem, see above resource for further potential problems.
To sum up, USB attached data disks for ZFS are noticeably less reliable than SATA, SAS or NVMe. You may have no problems in 5 years, but the only way to tell, is to try it. And then, if you have problems, the “correct answer” is going to be use a proper disk interface method.