There are small bumps on the F and J keys so that you can feel when you are correctly on the home row.

Yes, but then you need to bring your hands back to the correct position, and you’re lifting it off the keyboard. Which means you will likely be fumbling till you feel the bumps correctly.

With Vim and Caps Lock mapped to Ctrl & Esc I never have to completely leave the home row.

Can't say I have ever needed to fumble to find them, my fingers just land on them.

It’s sad that the best space for control keys is occupied by a pretty boring “ “ key, which is 6+ keys wide for some stupid reason.

> The only way to hit the ctrl key ergonomically

I just just use the side of my palm (top of fifth metacarpal) to engage C.

Super comfortable, low effort, no leaving the home row.