How to separate my account/phone from others (”organizer”)

Hi Apple Community! 

First, a short backstory: So, when I was younger, my dad put on parental supervision/screentime on my phone as well as using iCloud Family. A few years back, I stopped having contact with my father (for personal reasons) and have only stayed at my mom’s since.

Now all these years, I haven’t been able to download apps and other features,  because of the screentime restrictions. If I hadn’t figured out the code I would still have limited screen time too. But I really want to have an independent device and not have the slightest control from my dad’s side. I’ve asked him before to remove the not-being-able-to-download-apps-restriction but he said that he doesn’t have the control of that since I’m under 18 (jokes on him, my sibling over 18 has the same problem). My dad’s very good with technology so it’s not that he doesn’t know what he’s doing, he does it on purpose. I don’t want to have to contact him to correct the problems, so I was wondering if there is any way I could fix it myself? It has affected both school and my social life over the years. Furthermore, he was not the one who bought my phone, so he has absolutely no right to have such control.

I’m also wondering about the whole iCloud Family thing. I’m not comfortable with him having access to my photos, notes, messages, location etc. I would like to leave the iCloud Family, but I’m unsure about the consequences. Will my photos disappear? If I have photos from iCloud on my phone, will they disappear too? What about my icloud account? I use the “@icloud.com” email for a lot of other accounts, what would happen to them? My Game Center account? Do I have to transfer everything to a computer/USB? Do I have to create a new iCloud account?

I mean, my iCloud account should still be the same, but I’d rather be sure not to lose anything.

Could there be any more complications that I should be aware of? Is there any other possible way he could control or see things from my phone?

Extra information: I use an iPhone 8 with iOS 16.7.8

Thank you for getting this far and I would really appreciate any suggestions or solutions!