[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