Also I imagine just less processed crap and takeaway containers in general. They didn’t have plastic wrapped baked goods shipped from another country. It was just baked in the store you bought it and served on a plate.
Some glass bottles can contain more microplastics than plastic bottles...
I'm reasonably sure however that the glass bottles themselves are not contributing to the pervasive abundance of microplastics in the environment. The article also cites that it comes from the paint on the caps. I'm sure that can be fixed.
Since it appears to be from the outer paint on the cap, it's relatively straightforward to select bottles with unpainted caps.
In the article, scientists developed a procedure to decrease amount of microplastic in such situations: a blast of air on caps. But "just use glass" doesn't mean "microplastic free".