DC also can’t force us or the other States to accept it in as a State. So, who blinks first? From where I sit, retrocession is already a massive compromise where Maryland gets its land back, 1 to 2 House seats and a bigger tax base; and the residents of DC get the right to vote for not just Congressional representation but also for a State government.

It's absolutely a no-go. The constitution says that the seat of the US government will not be a US state to prevent favoritism for said state. There are some pitches for greatly reducing "Washington DC" down to the smallest possible constitutionally allowed area, but I don't see that happening. Republicans will not allow another Democratic state into the union anytime soon.