That's odd. I have an old Samsung from 2018 that seems to handle eight videos playing at once very well. It takes a lot to play a bunch of videos simultaneously on older devices, so you might want to check if your phone is running on battery-saving mode, or maybe you have other apps running in the background? Unlocking new sets of animations should not impact performance, as they are only loaded when needed. Check out the PC version if the issues persist.
Glad you like it! :)