you can pretty much just read the headlines:

https://www.npr.org/2006/10/12/6252448/hp-spying-scandal-offers-window-into-board-battles

https://www.pcmag.com/news/hp-accused-of-quietly-installing-spyware-on-windows-pcs

https://www.cio.com/article/260587/hp-spying-scandal-a-timeline.html

https://www.gsaig.gov/news/hewlett-packard-agrees-pay-united-states-55-million-settle-allegations-fraud

this is all ignoring their bricking of their own printers when you try to use 3rd party ink, though widespread enshittification is making that particular bullshit more common among different brands