Blocking an app/family sharing

Hi there I’m new to all this so hope it’s in the correct section. I’m having bother with my son and social media apps. Iv family sharing set up and he needs to get permission to download apps but because the likes of TikTok have previously been approved although Iv deleted the app he can still download it without my permission 🙄. I know I can restrict the age off the apps but if I do this to age 9 then he can’t access Spotify or WhatsApp (he uses this to contact his friends without iPhones for video calls). Is there a way I can block the app completely or change something so he has to ask permission to re download it? Iv tried deleting the app and hiding it via iTunes purchased lists neither make a difference it’s still as easy to re download.

Thanks in advance