[wao0uuno]

Official power supply is sold separately. Pis work fine with unofficial USB-PD power supplies but will limit maximum current for USB devices. I have two Pi 5's and one 4 and they all are perfectly stable when powered with an old Lenovo laptop charger.

[hedora]

It's still a huge pain point. I keep a magic "correctly sized, but provides clean power" USB charger with my Pi in a drawer, because I know that, if I lose that charger, I'm buying a replacement. It's unclear to me why they're so borderline. Maybe USB-C would help?

[wao0uuno]

I don't know much about older models but on 4 and 5 they chose to use a weird power standard to reduce cost. Just buy the official charger. They're not expensive.