I have a Monica and while I like typing on it I couldn't imagine writing anything substantial with it, the physical effort required to hammer down the keys hard enough is already quite fatiguing, even for someone enjoying mechanical keyboards. There are a few more modern electrical typewriters that I would consider for serious writing duty.

You need some time to switch from computer keyboard mindset. Even though it's the same thing, typing on a typewriter is completely different experience and the way you type is different. You have to place your hands differently, and get some muscles in the fingers since you have to hammer that key. Especially for ring finger and small one - they are the weakest. But as you type more you become better at it, works for basically everything else in life.

This is somewhat compounded by the fact the QWERTY layout itself is an inefficient legacy remnant of typewriters, whereby the most utilised keys would have a tendency to stick together if placed side by side, so QWERTY was envisaged as a way of spacing out these keys across the keyboard. Not for ergonomics or efficiency, but as an engineering workaround.