Can I build such things like a browser that opens a web page when you enter a url and an admin account can also mark website as unsafe so users will get a warning message when they attempt to use the site
Yes.
my question is how
MARK SOLVED
I may have solved your question. I have already created a browser in thunkable and its public. Check out this link-
https://x.thunkable.com/projectPage/5eda4af325338939a38cddbf
Very good. But i dont think it met what i needed, because there is no options for admins to flag websites as not safe
You can send a alert if it is not a secure web site.
If a website has http in the start you can send a insecure site alert.
If you use cloud variables (or the firebase component), you can store unsafe websites that admins have registered (I assume you need admins to login?).
Then, if you have the app check for that list on launch, and store the list locally, you can have the device check the list, before opening the link.
Maybe set the update to check the cloud database every day, and if it’s not up to date, you could force an update or something.
Here is the completed app. There is a new report unsafe site button. That leads you to a information page to fill out.
https://thunk.app/w/lUBAHvygk