I don’t have the best system (i7-7700k, 32gb ram, Win 10, GTX 1070), when applying filters, cuts, transitions, Shotcut doesn’t play smoothly for me either. But the final product plays awesome for me. Never had a bad export, except for the mistakes I make during editing.
You can always install a different version and keep your current version.
I wrote this tutorial: Multiple Installations of Shotcut - Windows 10
And you can always go back to what version you wish to go back to.
All of the versions are available here: https://github.com/mltframework/shotcut/releases/