Hi,
can a two-way connection be cancelled or activated after the column already exists?
Hey @Taigo! Just to clarify, are you referring to this functionality here?
If so, I am afraid you will still need to establish the 2-way connection when initially setting up the board. I am aware that this isn’t the most ideal process and will relay this with our team internally 
That said, I am happy to follow up with the relevant team as to whether there are any plans to improve this feature, and will circle back here once I’ve received a reply 
Hey @Taigo! I have recently heard from the developers who have confirmed that they’re considering making some changes to this feature as they have received much feedback about this. I can’t confirm an ETA, but it’s on their radar and I will keep you in the loop if I hear anything more!