What if I forgot my screen time passcode?

That does not remove the screen time passcode, which is included in the backup. If you forget a screen time passcode the ONLY solution is to set up the phone as New.

Unlocking passcodes have never been stored in backups. The screen time passcode has always been. In iOS 13 it is still there, but not in a way that you can recover or see it. If you don’t believe me create a screen time passcode, back up your phone, then restore that backup. You will find that it still requires the screen time passcode.

No I mean reset the device to FACTORY DEFAULTS using recovery mode, I have done this multiple times and restored the backup and there was no longer a passcode

You encrypt your backups

make a back up

use recovery mode to factory reset the device

finally restore the backup.

passcode gone

No.

You have to restore iPhone as new using computer iTunes.

Read here: If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

I have tested this

Passcodes were removed from backups since iOS 13

if you do exactly as you describe the Screen time passcode will still be there after you restore the backup. Really. As the myriad posts from other users have discovered.

https://www.theiphonewiki.com/wiki/Recovery_Mode

Instead of going to a 3rd party website for advise.

Read below quoted directly from Apple Support doc. : Use Screen Time on your iPhone, iPad, or iPod touch - Apple Support

If you can't remember a restrictions passcode that you set on a previous version of iOS, or you forgot your Screen Time passcode, you need to erase your device, then set it up as a new device to remove the passcode. Restoring your device from a backup won't remove your passcode.

That link describes Recovery Mode, which will allow you to restore the device to factory. That is all well and good if you restore to factory and set up as new. If you do not set it up as new, and restore a backup after restoring to factory, you will just replace the Screen Time password. The factory restore will remove it, but the restore of a backup will put it right back on again.