OK, so you have an error on Screen1. Sorry, you cannot delete Screen1, you either need to fix the code or re-build your app.
Did you added the new Switch component to your Project, you probably could remove it from your aia. The Switch is causing issues when users use a Classic Theme. Removing the Switch component, if you added it, or removing any code you added to your Project since it last worked might allow you to recover working code. Otherwise, post a Block image of your Screen1 here in the Forum and someone might look at it and provide specific advice.
Did you make a backup aia of your Project made before you started testing with the latest update? If you have that aia, use the code that worked before. Also, make sure you use the new Companion 2.52 with your Project.