Yup. I work a lot with MVTs and one of the headaches is, after you have your nice shiny state-of-the-art maps, turning them back into PNG raster tiles for all the various clients that can't natively render vector tiles.

This link is shrinking though! There's slowly growing support. Leaflet and OpenLayers are fundamentally limited by being canvas-based, so there's only so much they can do.

QGIS has one of the fastest, cleanest MVT renderers I've seen, but I don't know how easy that would be to extract out.

PostGIS is the best platform for generating vector tiles, but it's extremely clunky. On the projects I'm working on (eg https://vectorcharts.com/) I do extensive processing in PostGIS, but then encode to vector tiles in bespoke C++ code.