About a decade ago I had a thing going on (where I was a "dreamy" designer) during a 6-month gig turned 18-month-gig I didn't even really want to do, at an international business where my antagonist was working in isolation in an office 10hr worth of flights and a 3 hour drive away: it wasn't easy to just go drop by his office and be like "sup, let's fix this". It was slowing down the project we were both working on and I hated it - deliveries that I was ultimately responsible for got de-prioritized in favor of endless refactoring and "productizing".

It got resolved by me taking the flights, the drive, having a beer, planning out the follow-up phase of the project the next day, have another (couple of) beers, drive back, fly back. All that was really needed was the mutual idea that the other was not a threat, and face to face contact helped a lot with that; the beers weren't really needed but may have helped in opening up. This ended up that we both did some concessions in our wish-list, made it work. And 4 months later we delivered, transitioned the customer deployment to service, and funnily, we both left around the same time.

De-escalation is important.