Depends on the fridge, in my opinion. I don't need any door sensors because my fridge will beep at me if I leave a door open for 12 microseconds, and the freezer is pretty reliable, it's just the fridge that needs adjusting from time to time.

I just use a ThirdReality smart plug with energy monitoring primarily so I can see power consumption, but I still contend that this combined with the temp sensor is enough to let me know if there's a problem when I'm not home.

Also a 20 year IT person, but on the Linux server side. I do have an isolated network for IoT things that don't have local alternatives (pfsense hardware firewall, 24 port managed switch in the rack and ruckus APs), but I hate (hate) the enshittification of perfectly good hardware with software that exists solely to harvest my data so a corporation can have an additional revenue stream for the shareholders, and I will go pretty far out of my way to avoid giving money to companies that do this. Dreading the day my beloved dumb LG plasma TV dies.

What hardware are you running your HA instance on? Mine runs in an HAOS Proxmox VM with the USB port for the zwave dongle (for the locks) passed through. ZigBee coordinator is ethernet, so it's just plugged into a switch in the living room.