I've been forced to swap out my steel moka pot for a plastic water heater for a while now for coffee, and am extremely wary precisely because of this. Personally, I don't trust the cheap espresso machines working with these pods - not only are they full of plastic, they also taste way worse (in my humble opinion).
I think it's very difficult, if not impossible, to avoid all microplastics entirely. However, that's often used as an excuse to not avoid any. I think there are areas of life - this being one of them - where we can reduce exposure, and I reckon every little bit helps, you know? I love that you've been writing about this recently, by the way. Such an important topic.
Yeah, I would strongly recommend switching to a water heater made from stainless steel. Same problem as with the crappy coffee machines, but think if you make some small changes what you drink and eat plus avoiding microplastics in your clothing, one can make a significant reduction in individual exposure.