Ukraine needed to present a credible threat to cross there to pin Russian forces in the area. Now that it's basically impossible to cross the river, Russia can redeploy the majority of the forces to other areas.

Was it ever feasible for them to cross the Dnipro with heavy equipment though? It already seemed too wide for pontoon bridges?

Last fall, Russians have built and used several pontoon bridges over Dnipro for a few weeks, as they defended Kherson city and the Antonovskij bridge was rendered unusuable by HIMARS strikes.