iPhone 8 Restrictions lockout

I have an iPhone 8Plus and have been trying to remember what my restriction passcode was from my previous phone and everytime I try one, it automatically says it's incorrect and says I can retry again an 1 hour. I only use 2 passcodes, and neither of them work. I have tried using a default one such as 1111, 1234, and so on, but none of these work and every failed attempt locks it for 1 hour.

I was looking at some threads on here, but from what I could see, none of them had been updated to the newest version of iTunes, iOS and iPhone, so I am hoping that reposting it will get some newer responses. I did just back up my phone to iTunes on my computer (HP Pavilion 15 touchscreen) and would like to know the simplest way without having to jailbreak my phone or download a bunch of simultaneous apps/programs to find the magic code.

Any help is greatly appreciated!!