Streetcars, subways and LRTs do not require new fancy tire compounds to stop releasing microplastics. Their brake pads can, though, although I imagine that regenerative braking helps somewhat.

Bicycles are so lightweight that the amount they release is negligible compared to a car.

I wonder if rubber-tyred metros like the Montreal metro and some Paris metro lines release a lot of microplastics?

Agreed, and I like all those forms of transport, and use some of them when I can. But I do have to drive sometimes (for a certain definition of 'have to' of course).

We're not going to win these things by saying "just don't drive". Driving less is part of the solution, but it's not going to work by itself.