When I need desktop app for my personal needs, I'm still writing them in Lazarus (text editor, git client, music player, spreadsheet, image cropper, various oddball one off desktop apps). It works on Linux and windows. If it really doesn't need to be desktop (typically visual apps that works on different files in different local dirs, or opening it in browser would be awkward) then I make browser app or extension in vanilla js. If it can be both desktop or browser, I chose browser most of the time, Lazarus is not exactly pinnacle of bug free apps.