Yeah, a second hand old as shit hp, that’ll die on you so quick.
Not my experience. At all.
Edit: also all the “cash grab” parts… you probably already have those parts just lying around doing nothing.
Yes I sure have a proprietary adapter for their PCIe connector and a Pi case lying around. Just the case its about 30€ and suddenly it becomes as expensive as a second hand mini PC for 1/10 of the performance and reliability. See the problem now? Even with the power adapter, the RPI is picky and will require a decent thing that is usually more than your average smartphone.