I would have said Prusa a year or two ago but they've reneged a little on their open-ness. That was probably in response to Bambu being fully closed and gaining so much market share.

The Core line of printers seems promising and a big leap towards closing the gap towards Bambu's corexy printers but haven't used one yet and I've been out of the game a little. Bambu though is probably more of a high-end appliance type than Prusas more utilitarian feel.