I solved by my own. I did fresh install and using the script of @sdetweil to install MagicMirror and mmpm of @bee-mar install all modules I saved my old config that all stuff was easy and fast. Thanks for your help. Best, MaxxMagic

I fixed the problem by my self with a new board from Pollin and it works perfect! https://www.pollin.de/p/lvds-interface-pi-mt6820-vga-zu-lvds-810220 It is small and powerful and theoretically it works with all Resolutions the Inverter you can still buy at Aliexpress for your screens! If you need some hints let me know. Best