The Knicks were a better team this year when Brunson was not in the game. In the regular season and the playoffs.
I haven't seen the numbers but I remember the commentators talking about the Knicks had their best numbers in the playoffs with either Brunson on the floor without Towns or Towns on the floor without Brunson. And that they had their worst numbers with both Towns and Brunson on the floor at the same time.
It was really bad with both because they are both poor defenders. Against the Pacers, Brunson was -26 and negative in 4 games. Towns was +7 and positive in 4 of the 6 games.
During the regular season Brunson's +- per 100 was +2.1 but the on/off differential was -4.9. That was not the case the prior season when Brunson's differential was +11.8 which is elite and why he was rightfully a top 5 MVP player. It is clear he and Towns aren't a great fit, I'm just not so sure Towns is the one that you'd move. Brunson is a small shoot first PG that is a terrible defender. Depending on what you think of Curry, he is the only guy to win a title as his teams best player that meets those conditions. It is much easier to find a PG than a big man.
Now Towns is not a #1 scorer while Brunson is so that would weigh to Brunson.
The Knicks best option is to keep both and tweak the offense and the rotation to better maximize their strengths and better mask their defensive limitations. Not sure Thibs has shown the kind of adaptability that would be required for that. So I guess I'm saying if they can't move someone like OG for Durant, then maybe they should move on from Thibs who is seemingly in the D'Antoni level of coach i.e. a guy that finds something that works, but isn't going to win a title because he doesn't have the flexibility to make changes necessary to beat good to great teams.