Just to add.
A number of us install the Frontier version of ED AND the Steam version together, it’s just a convenient way to use two accounts without having to renew the login token every time you switch CMDRs .
The InfiniteScreen software ties itself to an executable which is gonna be an issue if you have multiple versions installed and it’s grabbed the “wrong” one. I know you can change the .exe path in the latest InfiniteScreen version. ie my defaulted to my Steam installed which is where my 2nd CMDR is (which I use much less often).