It's funny, the "modern" look has become a countersignal for me. If the app looks like a webpage, I instinctively don't want it. Not because of aesthetics, but simply because I've come to associate that style of appearance with a lack of (or awkward) keyboard shortcuts, featuresets dumbed down to a level appropriate for chimps, various nags injecting friction against getting work done (ads, feature tours, logins, update reminders, etc) and laggy, resource-squandering performance thanks to some kind of bloated rendering framework like Electron with multiple V8 hosting processes sprawled across chrome.exe instances or whatever.

Case in point, the Dropbox Simplified Desktop App was a huge improvement for me. It nails just about everything I ever needed their app to do, and removes all the user-hostile fluff I never asked for. Similarly, I found Windows 11 Enterprise IoT LTSC to offer an improved desktop experience compared to traditional Windows, thanks to its exclusion of a lot of the cruft Microsoft otherwise shoves down the throats of users who, as far as I can tell from frank discussions with many of them, likewise actively don't want.

I'm not saying your desire to make your app look polished means it's crap, but beauty is in the eye of the beholder. Just like fashion, I wouldn't be surprised if we see a shift in the aesthetics trend as more people discover a retro feel sometimes signals a better user experience.

Programmers and designers thinking the average person is a moron is one of the two reasons almost no good software is writren today.