Took to a Chrysler mechanic and a Mercedes mechanic, both confirmed it was the skreem.
Started with fob not working, then when car is opened with key, security system kicks in and locks down the engine. Fob and all electrical checked out, diagnostic confirmed skreem. Cost to fix skreem and PCM is $4300, or part out the car. Someone else shared about this fuse #9 bypass. Mercedes mechanic didn’t believe it at first, but it worked! Must disconnect from battery first, remove fuse#9, reconnect battery and start car. Mechanic said it needed to cycle a few times (not sure what that meant).