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.

I splurged a while ago and got a pre-assembled Core One. It worked great right out of the box and is has been worry-free so far. So far, I've treated it very much like an appliance with no tinkering on my part yet.

The machine is still quite hackable. Prusa publishes the firmware and CAD files for their printers, although the CAD files aren't under a fully open license. The support is generally nice to people who tinker with their printers and sometimes even seems to be genuinely invested in seeing tinkering projects succeed.