https://hackaday.com/2024/11/20/with-core-one-prusas-open-source-hardware-dream-quietly-dies/#more-734822

(I’m not English native)

One of the latest Prusa printer is closed source If I remember correctly Core xy

You are not completely wrong, they have one printer with closed sources.

This is mainly because consumer 3d printer have been developped by 3d printing enthusiast first and not a company, Prusa which was leader for some time used a lot of open sources project to build their printers. As it’s getting mainstream as time goes by more and more companies shows up with closed sources project sadly.