CS2 External is the conservative external-first Distort product for main-account style play, stream-proof workflows, radar, ESP, bhop, aimbot, and simpler setup.
CS2 Internal is designed for users who want deeper customization that an external-first product cannot offer, such as skin changer, model changer, chams, and more advanced legit or HvH settings.
If recording or screen sharing matters, read the stream-proof CS2 workflow guide. If you are playing on your main account, compare External first. If you want deeper feature control and visual customization, compare Internal.