@phy_lis 

There are Web sites on the Internet that can name device manufacturer from MAC address. That may narrow search for such devices, but if for example your Dell PC has WiFi network card from some third party manufacturer, you'll see that PC not as "Dell" but as third party manufacturer name, from network card MAC address.

For example, I googled if XIAOMI sells networking gear, and they do offer USB-to-LAN and USB WiFi adapters.

I can't share links on that forum, so just Google MAC address lookup and you'll find those.

I checked MAC address from your screenshot, these sites say "not found, possibly randomized MAC address."

In my household I have consistent set of family members' devices on WiFi and no visitors allowed to use Main Network, they are given Guest Network SSID. What I did is went through each mobile device at my house and configured it not to use private/randomized MAC address. 

I have also found that during initial setup of device with Android 13, when I configured it to use device MAC address, this setting was ignored after setup was finished. I had to reapply it again after initial setup and OS update, then it became persistent.

Windows 10 and 11, Android after 9, Apple devices - they all have to be configured to disable private/randomized MAC address on Main Network SSID. Start with those, and if you do not have visitor devices using Main Network, eventually you'll get them all and force them all to use device MAC addresses.

Unless, of course, you use Deco content filtering and (some of) your family members are not happy with that. Unfortunately, all parental controls and content filtering features in Deco are easily bypassed by changing device to use private/randomized MAC address.

As for "app keeps renaming my devices" you may wish to give more details, such as screenshots of device names "before" and "after" and with its MAC address not changed between screenshots.