Hi Alexis,
It is correct that vector tiles are not currently supported in DHIS2. We planned to add support, but it was delayed when Mapbox GL JS changed their license (no longer open source). For DHIS2 Maps 2.37, we have switched to MapLibre GL JS. We are also considering a switch to deck.gl: https://deck.gl/
deck.gl don’t have built-in support for MVT vector tile, and we need to consider the total bundle size of the mapping library as we are often used on low-bandwidth networks.
Short story: If we continue to use MapLibre GL JS we will likely add support for vector tiles in an upcoming release, but currently you need to use the raster version from your map server.