When you're ready for the next upgrade experience, try a clad pan (stainless on the outside, aluminum in the middle). You get the even heating of aluminum with the durability and ease of cleaning of stainless steel.
I cooked on cast iron for years before switching to clad. Cast iron's poor conductivity causes hot spots underneath the burner. With clad pans, you find yourself pushing the food around less to get even heat.
I often hear people say that cast iron conducts heat well, but that is easy to disprove if you have a gas burner: put some water in the pan and turn the heat up. You will see the water boiling in a pattern that matches where the flame hits the pan.
I like to fry frozen chicken in the cast iron pan, but it is always a bit of a nuisance that the center of the pan gets much less hot than the perimeter. My gas range has a fairly large burner with no flame in the middle.
There are a bunch of techniques to see the heating pattern of a pan and to show how poor cast iron is in that regard. I remember someone using parchment paper (maybe Harold McGee?). In looking I found someone suggesting a light dusting of flour [1]. Of course, an IR camera is the most obvious. I've also noticed water boiling in unique patterns, like you mention.
Be wary of clad cookware if you have a flat smoothtop electric range. In my experience clad cookware much more easily warps and refuses to sit flat, thus losing out on a lot of conductivity and efficiency. Clad is great with gas or induction though where sitting perfectly flat doesn't matter.
Or just stop using 7-10 on the dial (except for a boil). If there was a single thing that improved my cooking, it was learning to stop using Hi all the time.
The flat bottom clad cookware is the best for me on our smooth top electric range (which I do not like at all). Everything else has some amount of cupping so it’s just hot spot management even with our fancy heavy copper French cookware. But yes I make dang sure I do not warp our clad pans. They must be flat!
I cooked on cast iron for years before switching to clad. Cast iron's poor conductivity causes hot spots underneath the burner. With clad pans, you find yourself pushing the food around less to get even heat.