I am sitting here with HP's very first printer / scanner copier the PSC1200 on my right from well over 20 years ago still working fine and an HPCP1518n1 laser jet on my left that I got from govt surplus used in 2017, and it is a work horse that prints beautiful brochures for me.
I use aftermarket toner and ink with zero issues in bulk.
I had a LaserJet4M I'd trashpicked from a university. The odometer had rolled on the page counter, and it needed a new set of rollers. Ten bucks got it back to new condition. The main issue was that the toner (even aftermarket) had shitty or dry-rotted squeegies that meant toner leaked during use, and pages came out grey. I used that damned thing until I got in trouble in grad school for handing in grey pages.
Laserjet 4Ms were incredible printers. Rock solid, reliable, cheap to run. I used to work at a place that did personalised junk mail stuff, and they'd do it by laser printing in b+w over pre-printed colour, using a giant shelf covered in Laserjet 4M+s (with ethernet cards). They could churn out hundreds of thousands of custom pages per day with that batallion of printers, and ran it all with one teenager and a cupboard full of old printers used to donate parts.
They were constructed like consumer electronics aren't any more - a thick, sturdy bent steel chassis with plastic panels over the top. You could strip the whole thing down and rebuild it without very much specialist knowledge, and parts were cheap.
I took one of those printers when I left and continued to use it for many years. The only real issue with it was it was kinda slow and a bit noisy, otherwise it was perfectly usable. Eventually got rid of it when I moved in with my partner, but my dad still has it. I bet it still works.