It's likely just you. It could be due to how capable your PC (or whatever device your using) is, or maybe a reinstall might be needed?
The lag issues on Android have been a known problem for months now. This is from their Discord:
"The compression method I used for Android doesn't seem to work properly, unfortunately. It makes videos appear laggy, and it's very annoying. I have no idea how to compress them correctly. The videos are way too large, and I need them to be more compressed for the Android version—without affecting how they function."
With Android phasing out APK support, I'm not sure if this is still a priority for the dev.