HP ProDesk 400 G4 Mini Desktop

HP ProDesk 400 G4 Mini Desktop

Does this have an RGB port for a monitor?

It uses DisplayPort but you can use this adapter most likely:
Cableader DP to VGA Adapter, Gold-Plated DisplayPort to VGA Converter Male to Female 1080P(Black) https://a.co/d/22fzJwn

Or this cable

DteeDck DisplayPort to VGA Cable 6ft, Display Port DP to VGA Adapter Cable Converter Male to Male Braided Cord for Monitor Desktop Laptop Display Projector HDTV https://a.co/d/gm8jpBQ

Also huge throwback I haven’t heard RGB port in ages lol we always called em VGA

This is a multi port adapter.

CABLEDECONN Multi-Function Displayport Dp to HDMI/DVI/VGA Male to Female 3-in-1 Adapter Converter Cable https://a.co/d/cMjiwX2