Is the issue with unbound stopping on package install also known to affect uninstalls? I uninstalled pfBlockerNG-devel to upgrade from 21.02_1 to 21.02.2 (as per Netgate's recommendation, for lurkers), and the upgrade page took forever to load. I found unbound was not running. This was on an SG-2100.
I recently did the same thing on a PC going from 2.5.0->2.5.1 and did not have that issue.