Putting this out there in case it helps others.
I kept dorking at this, tried again when 23.05.1 came out, but still couldn't get the upgrade to work. I opened a support case online, truthfully not expecting a lot of help (I have the free home-lab style license, no support).
Netgate TAC responded very quickly to the ticket (maybe 15 minutes), reviewed my notes, and requested remote access if I was ok with that. I didn't have an issue with it, provided them access, and after some digging, they found an issue with how I was loading my Solarflare 10gbe NIC.
I found two ways to do this, one using /conf/config.xml with <earlyshellcmd> and the other was in /boot/loader.conf.local. I chose to use config.xml because I used that for something else, it was easy enough.
The issue was in how the NDI was being calculated; the 10gbe NICs were not being included in the calculation.
TAC stated that the proper way to load the NIC driver was with loader.conf.local. They made that change, I rebooted, and had a new NDI. I already had a reg key I created a month ago because I thought it was a license key issue. I stuck that on, and upgrade was good to go.
This was my first exposure to Netgate TAC, and I was really impressed. They were very quick to respond, even though it was limited to the ticket (not live/phone/chat, because, I don't have a support contract). Also taking into account, this was my hardware (Dell R210ii), not a Netgate box.