How can I adjust my child's settings on the iPad?

I am pulling my hair out with family sharing. We were given an iPadPro and decided to use it for our kids schooling. Here I am setting up content restrictions and I seem to have gotten myself into an inescapable loop.

> Logged in as my own iCloud ID

> Added my kids under family sharing (at this point I thought you could just easily switch users.... like on Windows... silly me)

> Added content restrictions; screen time, app use, explicit content etc

> Couldn't figure out how to "log on" as them to test it. Did some googling, discovered it has to be logged in to one person. Best bet, the youngest child's settings.

> Logged on to the youngest child's account (with restrictions)

> Tested it by going onto Safari, at 11pm. Up comes my time limit restriction; great! However, there is an "ignore" option. Not so great.

> Also tested content restrictions by searching something explicit in Safari. Up comes a thousand links to PHub, despite me having restricted content in the family sharing setup. Also not great, for an 8yo's account.

> Googled some more. Found out you need to have a setting toggled to "block when time's up" on the adult account to stop them just endlessly ignoring time limits.

> Went to swap back to my own account to change this setting... to find out log out (of child's account) is greyed out.

> Google again; discover you have to remove restrictions to allow them to log out.

> Try to log onto my account in browser to change the restrictions - but I can't. I have to be on an Apple device.

Here lies my issue... I only have this one iPad Pro.

How the **** can I adjust my child's settings?! The iPad is essentially useless right now because I am not allowing my 8yo unrestricted internet access

[Re-Titled by Moderator]