So I figured out how to save your character (mostly)
\AppData\Roaming\7DaysToDie\Saves\'MAPNAME'\'SAVEGAMENAME'\Player
You will find 3 files that are named EOS_'bunchofnumbers' .map .ttp and .ttp.bak
If you copy and rename them to Steam_'youruserid'.map and .ttp (you can probably skip the bak file)
Easy way to get them would be remove the EOS from Crossplay and it will create them for you so you don't have to worry about getting the name wrong.
Now I say mostly, because my drone shutdown and locked and my bike is locked, and I imagine I am locked out of other things, but at least they are easily fixable with the DM. Probably best to move these things into your inventory before making the switch. And my turrets...yeah, and I seem to remember being able to select and unlock things (like safes) but that doesn't seem to be a thing anymore. Anyone? Oh, and your LCB...so this is a @%$#ing pita. LCB at least you can just give yourself the dev SMG (super digger) and remove and replace it. Really better to just start a new game probably, but I wanted to see if it could be done, and it can.
The Openresty thing seems to work, since without it you will be forced into offline mode (which also kinda works), but c'mon it is wrong that one should need to go through all these measures to bypass this crap. It is too much for the average person and that's why most of them just sit there and suck it up. I mean y'all already got my money so you can ignore me all you want, but you aren't going to get anymore out of me in the future if your next product has this crap embedded in it so obnoxiously, of course the rate you guys work, I will be dead before this game is out of alpha 😛
I also haven't tried online play with it yet, although obviously EAC has to be disabled on the server(s) you play on.