That's a bit of a pain if you put that into muscle memory and use other Vi interface software that can't be remapped.

Personally I'm in the Caps to Ctrl and use Ctrl-[ for escape camp. Works in my shell, REPLs and in my database clients and anywhere else with a readline interface that isn't Vim.

Even with that I still want a physical escape key.

how do you type "e_{ijk}"?

jk is a pretty rare combo to begin with, but when you do need it, just hitting j, and pausing for a second takes that input singularly, then you can type k safely. Slightly sub optimal, yes. But the benefits outweigh the negatives for me.

For example by typing: e_{ij<c-v>k}