I'll concede that native GUI development is tedious on pretty much every platform in existence. However, there was a golden age of Linux GUI programming that spanned from the mid 2000s to 2019, where you could spin up fantastic GTK interfaces in the span of a weekend afternoon. I still use GTK3 to make simple forms and utilities, and I reckon I will for quite a few more years; the workflow is flexible and straightforward, there's a ton of fantastic desktop widgets that work as well as they do on a touchscreen as they do with a mouse, and it was surprisingly extensible too. GTK4 has seemingly put that behind them to focus on a "write your app in this specific way or don't write it at all" ethos, but frankly I'm happy to stick with the prior toolkits. Maybe it sounds cheesy, but it really was my "ideal" GUI library for a while.