How can I unlock my iPhone without erasing everything

Sorry, that is not possible. If you forgot your passcode, you will need to reset your phone. Hopefully you made backups kups you can restore from after you reset it.

If you forgot the passcode on your iPhone, or your iPhone is disabled or unavailable -

Click on the link for instructions on how to reset your passcode without a computer if you have iOS 15.2 or higher.

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

Click on the link for instructions on how to reset your passcode using a computer.

If you forgot your iPhone passcode - Apple Support

There is no way to avoid erasing your phone if you have forgotten your passcode. Assuming you've been smartly backing your iPhone up, you can restore the most recent backup once it has been erased and you're back in. If you haven't backed up your iPhone, it's too late to worry about losing your data as it's gone.

You’re going to need to try and remember the password. Or hope you have a recent backup you can use.