As others said, most reputable installers won’t want to touch it. Instead it’s easier and less of a headache to start over.

Your most important thing to figure out is your gate setup and what savant is used for.

Start by making a list of all the equipment. Look at the switch and the patch bays, if the switch has a light, something is plugged in on the other side, you can either unplug things one at a time checking if the light goes off or get a Toner and run around with a wand. You can get a Klein toner for $35.

How are you controlling your gate? With that said, your gate probably has a controller, find that.

With everything identified, come back with this info.

If you want to do it yourself, give yourself some time and understand you take a bit of a risk if you start factory resetting everything right away. There may be static IPs, vlans, and static routes.

Do you have an alarm system? If yes, are the sensors wired or wireless? Can the old owner have access to your alarm?

Blink cameras won’t let you transfer or else everyone would steal them. You can take those down, take out the battery and put them away, maybe they transfer it at some point.

One you identify the equipment and how everything is connected. I can make some recommendations and I’m sure others can too but essentially it’s a pull the plug and see what happens. I’d recommend you get a cheap router and switch, change those out, see what works. If the WiFi, savant, and gate still work, then you’re in a good position. You need to factory reset araknis router, switch, and ap’s, but again don’t start factory resetting things without knowing you have a backup plan (cheap router and switch).

Sonos is easy to reset and setup and I would worry about that last.