Ive done a few hardware migrations over the years.
Create a backup, download the backup and store it in two separate locations. (you should be doing this regularly already)
Copy the YAML based config of any add-ons to a file so they can be easily restored if it doesn’t happen automatically.
Get HA loaded on the new system (not a full restore but get it installed and to the logon screen).
Properly shutdown the Pi4 (don’t just pull the plug). Keep the Pi ready to go incase things go south. If they do go south with the new machine, you should be able to plug the Pi4 back in and be back up and running.
Re-assign 192.1689.1.23 to your new HA hardware (restart the new HA hardware as needed to get it showing up with the 192.168.1.23 IP).
From the initial setup screen, restore your backup
Be patient and wait. Depending on the power of the new machine and size of your configuration, it could take awhile to restore the backup.
Once fully restored, log in and see if everything restored correctly. I generally have seen the core config restore every time add-ons can be a different story in my experience. Things with hardware specific configurations may not restore correctly and need adjustment.
Hope that helps, generally its a quick and easy affair.
In case you have Z2M/Zigbee devices in place you should also backup its configs and database! You’ll find those files inside /usr/share/hassio/share/zigbee2mqtt
configuration.yaml
database.db
devices.yaml
Shutdown Z2M before copying those files over!
On the new system copy above 3 files into the new zigbee2mqtt-folder before starting Z2M the first time.
This saves you from re-pairing and reconfiguring your Zigbee network.
I’ve just migrated from a Raspberry Pi 4 to an Intel NUC, and it worked like a charm.
The only addition I would make, is to do a complete reboot after the restore process. None of my add-ons would start, but I quickly found out that it’s a known problem after a restore, and the complete reboot did the trick (Add ons not working properly after snapshot restore - #19 by kennethpangky)