Both types of systems exist, but from what I've seen the indirect TPMS systems you're describing are becoming less popular. I'm somewhat familiar with Mazdas anyhow and that's the way it's going with them.

For 2017 the Mazda6 used an indirect system: https://www.mazdausa.com/static/manuals/2017/mazda6/contents...

For 2020 it's a direct system with in-tire sensors: https://www.mazdausa.com/static/manuals/2020/mazda6/contents...