You would have to ask them. I think they make it a practice to not restore apps from backups (because they would be overwhelmed with requests), so I don’t know if you will have any luck there or not.
Just some advice for the future…backup, backup, backup…if you can. I have a Google app script that automatically creates a timestamped backup of my sheet every week, so I always have a backup copy if data gets deleted or if something major goes wrong with the sheet itself. Periodically I will also create a duplicate of my app (with or without duplicating the data), in case I accidentally destroy something. I know some people have had issues duplicating apps connected to large sheets. I haven’t had such issues, so I can’t say what would be the cause in those cases where it doesn’t work. I suspect that in your case it was messed up because you already had data connection issues, so that may be why you couldn’t create a duplicate.
Unfortunately Glide doesn’t provide any good and reliable backup/restore functionality for data and apps, so we kind of have to hack something together ourselves the best we can. I’m sure they are well protected if they screw up on their end and they do have the ability to restore backups in those cases, but they don’t have anything for us when we screw up.
Always hope for the best, but plan for the worst.