I forgot my passcode for my old phone what should I do?

To unlock your iPhone, follow the steps described in the Apple article:

(< iOS 15.2) ->: If you forgot your iPhone passcode

If you forgot your iPhone passcode - Apple Support

(iOS 15.2 or iPadOS 15.2 and newer) If you see an iPhone or iPad unavailable message or Security Lockout screen

If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support

I also erased it from my Apple ID just a few min ago?

Try to add again to your account, see -> Check your Apple ID device list to see where you're signed in

Check your Apple ID device list to find where you're signed in - Apple Support