You have 498 blocks on the first screen “gpac” alone. That’s a lot to look through to try and help you.
You will need to do some debugging yourself. I have a method I use that helps me find where a crash is occurring: Debugging in Thunkable X (Video).
If you know where the crash (error) occurs, post the details of where that is in your blocks and what you’re doing (just loading a screen or clicking on a button or typing something in…) that causes that to happen.