I am having same exact issue in my zoo where I added a souvenir shop. I was able to find an older save file and played in that last night but now when I open that file it also crashes and it does not have the new souvenir shop
The support team just sent me an email saying this:
We have been noticing some of these cases have some commonalities within them, and we are investigating these as a priority. It may be in a future update, we fix this and get things working again, so you can load into this park with ease.
I know this isn't a certainly and I do not dare to get my hopes up that my zoo can be saved. But it is some sort of comfort to know they are looking into it.
It is odd that you can't load you zoo through from a backup save. Maybe it is the update itself? But, usually that works. Did you experience anything when the game crashed? For example a blue screen or your device shutting off?
I guess all we can do is wait for the next up date like Captain Callum said.