@retroedgetech i only really started.to use tcl a few years ago., previously i only used it for eggdrop stuff on quakenet ;).. i build some private tools with it, i found it's really nice as replacement for advanced shell scripting and for smallish gui tools. also Tk is really nice compared to any other gui toolkit i have used. small in size and useable, with the themed widgets it's even nice looking and on top everything is rather portable. i guess tk would profit from an opengl style rendering backend for even better portability.
tcl is both small in language size but huge in the orthogonality of it's features, it's a bit like go in this regard.
i found this tcl book to be very nice because it also covers modern tcl (like TclOO): https://www.magicsplat.com/ttpl/index.html