Passcode not working

If your iPhone is running min to iOS 15.2 you don't need a computer, see:

How to reset your iPhone, iPad, or iPod touch when you forgot your passcode

How to remove your iPhone, iPad, or iPod touch passcode without a computer - Apple Support

If not:

Ask a friend, acquaintance or family to use their computer, or at a public library.

Alternately, visit your local Apple Store or Apple Authorized Service Provider and they should be able to help you out.

You will first have to make an appointment due to the pandemic.

Call Apple in your region see: Contact Apple for support and service

Contact Apple for support and service - Apple Support

FYI......You won't get locked out unless you enter the wrong passcode 10+ times, so you were likely using the wrong passcode.