Am eagerly anticipating the commercial availability of Mathpad.

At the moment I'm using Espanso, an open source software that lets users map typed character sequences to unicode. So it's possible to set things up in such a way that typing the character sequence ";" "a" ";" makes Espanso replace the entire ;a; string with the greek symbol alpha α.

Symbols like ⇒ that can kind of be "drawn" with common keyboard characters "=" ">" is possibly nice to be mapped to the character sequence ;=>; This is a personal preference inspired by Typst's math notation design choice.