I used to do exactly the same. But then I developed RSI in my left forearm, which I blame on overusing it for all modifier keys (including CapsLock as my only Ctrl and only using left shift).
Afterwards, I used a Karabiner Elements script to completely block myself from pressing a left-hand modifier and left-hand letter key simultaneously, forcing myself to learn proper two-hand typing of modifiers. My arm feels better now, and I’ve actually finally appreciating having a Caps Lock key precisely due to the struggle you describe - I’m convinced that two-hand chording is healthier than pressing multiple keys simultaneously with one hand, but at the same time typing e.g. TODO out is then unbearable without a real caps lock key.
I actually like the concept of foot pedals or thumb cluster keyboards, which sound like two of the most ergonomic ways to use modifier keys.
The main issue is that due to my work I have to regularly work on a laptop, and anything that deviates too much from a standard keyboard will cause too much friction as I switch back and forth. It would have been easier to go all in on custom hardware if I worked at one desk all day.
Afterwards, I used a Karabiner Elements script to completely block myself from pressing a left-hand modifier and left-hand letter key simultaneously, forcing myself to learn proper two-hand typing of modifiers. My arm feels better now, and I’ve actually finally appreciating having a Caps Lock key precisely due to the struggle you describe - I’m convinced that two-hand chording is healthier than pressing multiple keys simultaneously with one hand, but at the same time typing e.g. TODO out is then unbearable without a real caps lock key.