Yes, it’s secure and of course can be further secured by other services, like vpn and scanners and such. I front my stuff with Cloudflare certs on their free tier as well.
Just use complex passwords for the admin and logins. They also support two-factor authentication which is easy to setup.
iPhone has a feature called screentime that allows you to monitor usage of application categories or individual applications. You can put time limits on these categories or applications to not allow you access them without bypassing a screen if app usage exceeds that time limit for the day. It then resets the next day.
Not sure if android has this capability, only telling you what I have experience with.