The espresso maker is a stove top, and I am unable to find a way to use it on the induction cooktop. I want to make decaf with milk and that is filtered coffee, not instant coffee.
It sounds like the only thing you can do is use an interface disk - basically a piece of metal that is compatible with the induction cooktop, which will then transfer the heat to the espresso maker.
You can also potentially use an induction-compatible pan as an interface - see this question.
Unfortunately either way, you'll lose the fast-response benefit of the induction cooktop, because you'll now have to wait for the interface to heat.
This answer assumes that you are using a moka pot.
Though you don't state it explicitly, it seems to me that the problem is that your espresso maker is not compatible with an induction stove top.
The solution, then, is to get one that is compatible.
I have tried with some success "bain-marie". I put the coffee maker in a pot with water and make it boil. Sometimes it works, sometimes it doesn't, I don't understand why.
See previous answer? I would expect the outer pot acting like the mentioned disc playing a greater role than the water.– Stephie ♦Apr 17, 2021 at 5:30