Solved for now. Thank you everyone for your help.
I went with the CLI route. The CH64 observation above doesn’t seem to be causing any problems without changing it.
For later reference, this was the process I followed.
Install CLI using the link posted above by @descartes in Request - DevMode toggle or Reset Nonce button - #14 by descartes
Create a file called ttn-lw-cli.yml and save it in wherever you want.
Go to https://www.thethingsindustries.com/docs/reference/ttn/addresses/, select your appropriate cluster, scroll down and copy the addresses in the CLI section into ttn-lw-cli.yml, then save.
Navigate to the install location of ttnctl. On my mac it was /usr/local/Cellar/ttn-lw-stack/3.12.3/bin.
Now tell ttnctl where the configuration file is. I used the command line option from https://www.thethingsindustries.com/docs/the-things-stack/interact/cli/installing-cli/
Now that ttnctl is configured, login by following the guide linked above.
Once authenticated, it’s time to change the devNonce flag.
The command I ran was:
ttn-lw-cli end-devices set --application-id “my-application-id” --device-id “my-device-id” --resets-join-nonces “true”
After doing this the node is back up and running.