Branching Scenario Button State Changes Based on Variables

I am trying to create a branching scenario where a variable triggers a button to become disabled after successfully completing a scenario. Here is what I'm trying to create: on the first slide, I want the learner to have 3 different options of scenarios to pick from. They need to click a button that brings them to that corresponding scenario which is branched off on a different slide and not a layer. On a given scenario, the learner has the option to either complete the simulation OR click a button that exits that scenario and returns them to the first slide if they change their mind and want to do the scenarios out of order. If they choose to complete the simulation and do so correctly, there is a button to submit their answer that then takes them to a layer which will act as a pop-up. On the pop-up layer, I have a button that will return them to the first slide as well as change a T/F variable to True. When they have returned to the first slide, I want the T/F variable to trigger a state change for the button to become disabled. I can achieve the state change when all branching scenarios are done through layers, but based on client needs, this needs to be a branching scenario on their own slides. I also don't want to trigger the button to become disabled when the user clicks it because I need the learner to have the freedom to enter a scenario, change their mind, leave and come back to complete it later. I have the first slide set to resume saved state and my storyline version is Jan. 26 (3.72.29699.0). Our team is not allowed to update until given the go-ahead by one of our veteran designers after testing has been completed. Is there any way to get this working? I have attached a skeleton version of the course here with just the one scenario, along with some notes on the slides. Thanks so much in advance!