Just take out the wifi module. If you need wifi just use a USB adapter. That’s your kill switch.

I enjoy a program called Alldup. It’s quite nice for my uses

Could I recommend changing the HDD to an SSD?

Really helps the snappiness of the computer.

I have a lot of SSDs at home and I wouldn’t mind shipping one to y’all since I also live in Germany

I’m a big fan of Mikrotik with Unifi WiFi.

Mikrotik I have a RB5009 which is powerful enough for all of my needs.

I often skip first gens hence why I got a 12th gen and then upgraded it to a 7040 series. Super happy with the battery life and performance.

Maybe liveboot it and do a smart test on the drive?

I’m using yubikeys. Works fine on Linux and Android.