You can't build your team around matching up with just one other team. If BKN is fully healthy, they may be the team to beat. Or something else might change and we need to beat an even different type of team (maybe Philly gets Lillard or something). But that said, I do feel that we need more skilled size to compete as a general condition, not just because Giannis is so good. So yes, Jaylen Brown for Towns works for me. There are not many I would trade Brown for but Towns is one of them.
Maybe Moses Brown or RWilliams will be able to slow down Giannis. Or maybe we decide to play a zone defense. With all the picking and switching, the one on one match up (Giannis vs. Towns or whatever) doesn't seem to matter that much. Just play good team defense with the best guys you have and if Giannis still goes off for 50 pts, what can you do. It looked like PHO was doing everything they could. Doubling and even Triple teaming him. He was still getting buckets. PHO has Crowder as their principal PF, not a great match up (also not horrible), but I am not sure that mattered.