[LeifCarrotson]

Polish is great, but it sounds like your customers - enterprise users with many hours in your app - are of the sort that would benefit from an ability to help themselves. You're not in B2C, you're in B2B. Add features (because that's what your boss is measuring) that give your users enough rope to hang themselves, as they say.

In the event of a crash, they are likely able to choose to either start over and drop the last 4 hours of work, or to load state from autosave-20220507.1300.xml and retrace their steps from the last 5 minutes. Or improve your logging until it's user-accessible, with the goal of giving them access to a file they can read and figure out how to reproduce the crash (and avoid those circumstances in the future) or send to you to help debugging.

Absolutely give them an API: Your customers are literally offering to help you do your job for you! If you can swing it so their plugins run serverside and you have a license to the macros they're building, you'll soon see exactly what they need and be able to anticipate those features for other customers. If your product requires special features and you're being told by your customers that they can't convince management to buy it until it supports feature Z, give them the tools to build feature Z so the answer to "Can you integrate with our ERP?" is not "we could add that feature after we finish integrating with our other customer's ERP, talk to you again in 3 weeks" but "Does that ERP support XML? JSON? CSV? SQL? Sockets? Regardless, we can help you write a simple plugin to accommodate whatever specific needs you might have."