You may be able to get 3rd party ones to work but if you use multiple profiles then you'd have to get your dad to set it up per-profile and it would count as a different phone, which many charge more for. I suggest talking to your dad about removing it, some suggestions for things to bring up are.
- Its a privacy risk: Family link gives Google a crap ton of data on you, going 3rd party like you may have to for GrapheneOS means simply giving it to another company. Idk about you but I trust Google more to keep the data to themselves then I do shit like Bark.
- Its a security risk: Most of these apps are going to require them to be at least set as device admin and as a VPN to work properly, some may want root access, meaning if their server gets compromised then someone may be able to do things such as remotely wipe your device, change your devices screen lock, listen though your devices mic and see through your devices camera (on the more invasive ones), etc.
- It may harm the relationship between you and your dad: I won't speak for you but if my parents spied on me online it would severely harm the online relationships I have and just general enjoyment of the internet and in turn make me loath my parents. Parents aren't magical and imo usually aren't acting in your best interests when it comes to the internet even if they genuinely believe they are, they may consider something harmful to you and prevent you from accessing it when they really should be educating you on why its harmful and give you the choice of whether or not you'll continue accessing it. Authoritarianism in the name (but usually not in the best interests) of children whether by parents or by the state shouldn't ever be tolerated as it ends up leading to censorship of things that the people in power (law makers, parents) simply don't like. I wouldn't blame him for this though, its made out on "parenting" websites that parental controls is the best thing he could do for you online so it doesn't mean there is malice involved, though there still could be.
Hopefully he'll reconsider the spyware, GrapheneOS is the best of the best but the apps you run on it make or break the privacy it comes with.