Video resume Storyline project freezing and absent of animations/transitions in mobile view

Hi! I made a video resume using Storyline 64-bit, though I've had the same problem with this file in regular Storyline 360 (attached). It plays fine in Chrome or Firefox on a desktop or laptop, but on any phone or in Safari, it freezes about halfway into the "whole enchilada" button option and also in the other button options at various places. What's even odder is that the transitions and animations do not work when played on a phone or even when previewed in Storyline in mobile view. I could live with that, but the freezing is the real problem. I do have multiple videos playing at the same time at some parts. Most of the videos have been optimized with handbrake to ensure they are still high visual quality but smaller in file size.

I've searched the web for solutions and tried many things, none of which work. I tried to export single slides of this project as a video (duplicated the project and deleted all slides but one and removed most triggers except essential ones) to see if I could eliminate the problem by consolidating videos and having less objects/videos overall. No matter how I tried to export a cut-down project as a video, the export appeared to begin fine but the blue export progress bar would go on indefinitely...as in over 12 hours...and then just cancel itself.

Can anyone tell me what I'm doing wrong or where the problem is? Why is this project playing fine on most desktop browsers but not on any mobile device? Any work-around advice or fixes would be much appreciated as I've spent a month trying to fix this unsuccessfully.