> and what a pain in the ass it was to find the specific symbols I needed.

But that's exactly the same issue with the hardware solution - you can't use Ctrl+F to find by name and you can't see all the many symbols on the keyboard itself. You'd need a software solution to show a visual searchable "cheat sheet", and also you can map more mathy keys to an existing bigger keyboard, where entering some symbols will be way more natural, e.g., for greeks you can map most of them to different A and B latin keys instead of having both αβ on the same key. Similarly, you could do map ℤ to Z and ℕ to N, so these would be simpler to remember/input than using a dedicated keypad, so the printed symbols on the keypad aren't that useful anymore.