I am using a Stream Deck for that. Should have bought the largest one, but even the medium size on is quite useful via nested menus. Here are some symbols I am using for a formalisation in Isabelle currently: โโโคโฅ๐๐โฝโ๐ฐฯ ฯโฃ๐ญโนโบโ รโโ
Something like the DuckyPad[0,1] might work for that as well. I haven't tried using mine for APL or anything like that, but it's been great for use as a "Zoom meeting control", numpad, and MacOS shortcut pad.
