[nephanth]

I generally heat half the water in the pot, and half in the electric kettle (adjust proportions depending on the relative power of your appliances) Quickest way to heat up the required amount of water

[koliber]

Assuming you have a four-burner stove, you could split your water five-way, and use four pots and your electric tea kettle.

If you want to push, you could improve the efficiency even more. That would require a capital investment into additional stoves and/or electric kettles. You'd probably need something like kubernetes for orchestration as well.

[nephanth]

Since I don't have a dishwasher, using more pots actually has time cost, so that approach doesn't work

Interestingly, I feel compelled to wash a pot even if I only used it to boil water, while that's not the case for the kettle. Force of habit I guess