I want to get stronger without getting bulky

That's a great attitude, focusing on substance over appearance. High-weight, low-rep training will condition your nervous system and build solid strength. Be mindful of overconsumption and focus on fundamental power.

They say high weight, low reps with sufficient rest is good.

I recommend boxing or Muay Thai.

I'm curious!! I really want to know too.. 😭

If you're talking about weightlifting, for hypertrophy, it's high weight, low reps. But honestly, even if you lift weights to build muscle, it grows incredibly slowly, so you can pretty much do whatever. Of course, you have to consider that some minimal muscle will build regardless of the exercise. If you tell me what exercise you're doing, for what purpose, and what your current situation is, I can give you more detailed advice!!

Does the strength of martial arts increase significantly in proportion to body size?