Not if you have a keyboard with easily reflashable and programmable firmware (such as the Moonlander). If the firmware has built in support for layers it becomes trivial as you can just have a QWERTY layer activate when you hold down ctrl etc (Moonlander also)
It's actually quite easy! Of course, I wrote my own firmware for the keyboard I use so I'm biased, but most mechanical keyboards out there support QMK/VIA these days which makes it quite easy to create custom layouts and "layers" that activate based on what modifier keys are pressed.
Creating that firmware was one of the most fun and satisfying projects I've worked on in a long time.