Falter is throwing a lot more fastballs 51% (at 91.8 mph, about his 2021 velocity), and has ditched his change-up, he is mainly FB, CU, SL, SI these days. I think his FB was considered an average pitch at best, but throwing it about 20% more has given him more success. Probably locating it better in the zone.
Pitching in Pittsburgh is a different mental ball game, too. I always got the impression he was pressing here.