Homegear thing config changes itself in paperui

I have a probably pretty basic problem since i switched to rpi4
My homegear binding / thing for the homematic bridge should have (or
If i set it up like that in paperui it works pretty fine including the items.
But after a restart it sets its ip to
Which is I think the ip now of the other Pi that was running shortly as a backup / for the setup

I couldnt find a config file for that yet. Does anybody know how to lock that or configure that in a file without fucking up paperui?

PS: different topic but maybe somebody can answer that too:
I jave hdmiblanking set to 1 but lightdm only turns the screen blank and not off… does anybody know where does settings are?