I have this message iPhone Unavailable try again in xx minutes how come I got this message. I don’t want to reset it. I just want to gain access as before

You, or someone tried to open your phone and entered the passcode incorrectly too many times. If you wait and can enter the correct passcode, you won't need to reset it. If you have however, forgotten the correct passcode, you will have to erase the phone.

The Related Article link at the top of this page, which brought you here explains this.

Wait until the timer expires and then enter the correct passcode.

If you continue to enter the wrong passcode, you will be forced to erase / reset the phone. No way to avoid this.