Pine64, the company that has made such excellent projects as the PinePhone, PineBook, and PineTime(open source hardware and software smartphone, laptop and smart watch), has stated that one of their dream projects would be an open source, hackable printer. There’s obviously a ton of logistics though and it will likely never materialize unless they really start making big bucks.
They only mentioned it in passing once (afaik) in a blog post. These aren’t actual plans so much as a pipe dream I think