I've been using an external portable (2.5") seagate drive[0] for a while with my pi 4 to hold music and videos. It's plugged straight into the USB 3 port with no problems so far.

You will have problems trying to power a desktop 3.5" drive though.

[0] https://www.amazon.co.uk/Seagate-Expansion-Portable-PlayStat...