Rush app crashing on iOS. Can’t export, play or edit a project.

So, I've been using the free Rush app now for a few videos already. And the past projects have already crashed a-lot but this one is worse, I managed to export fully edited, finished videos in the past, and they were in 4k. So my free exports are done and I'm now exporting in 1080p. I recorded a video for YouTube in 960x480 resolution and it's an hour in total but consists of a 15 min, 25 min and 12 minute long video. And now, I've managed to edit almost the first two clips into a 5 minute-222MB file, but I just can't finish it because of the crashing on my iPhone 8. So what I did was I took the last 12 minute clip to another project, fully edited and exported it. Basically I divided it into two projects named part 1 and 2. No matter what on earth I do, I can't manage to export, edit, play the first part because of the crashing, I did everything to my power. I tried dividing it into sequences to export shorter clips at a time but to no avail, I tried everything. I even reached out to an Adobe agent, and there was nothing she could do about it, she just told me to reach out to the forum by posting here, "there's a team dedicated to this here" she said. Please help me, this is so frustrating. My video was supposed to be up a week ago. This problem has also been pulling me back from getting the premium subscription, I'm scared that I won't be able to use it.

My 4K mov vids that succeeded were filmed on my iPhone (this phone) and the mpeg 960p vids were filmed with another phone. Just thought of adding that. I'd really hope to fix this. Thank you so much!