A good manager will ensure everyone has actually read Filthy Rich Clients, is aware of Swing theme component libraries and never does IO on the UI thread.
And for bonus points, that the team gets hold of an Java AOT compiler to native code.
Of course JFX is probably a better option now days but for a small GUI if you avoid layout managers like GridBagLayout (built to work with a WYSIWYG) and you are on the JVM seems like an easy option to me
http://tktable.sourceforge.net/tile/screenshots/windowsxp.ht...
https://www.tcl.tk/man/tcl8.5/TkCmd/ttk_intro.htm
I wouldn't base any commercial product I'd make on Tk, if it was meant for a large audience. Internal tools where you get to tell you users: "shut up and use the ugly app cause management already paid for it", ok, there you can use it. Otherwise... no.
How about a dated looking Electron "app"?
Cross-platform desktop apps with reason
Personally I'm a fan of C# with WPF, but while C# is decently cross-platform with .net core WPF is Windows only.