request new sim from phone provider, change phone number (make sure you don’t lose 2fa keys)

set up Bitwarden or some kind of password manager

Change email, set up min 16 character password

Factory reset phone

Create new iCloud with min 16 character password

do not restore from anything and do a fresh install

Reset all passwords with min 16 characters passwords, no password should be reused

Disable all analytical and tracking info on phone through settings (Michael Bazzell has a great guide on this)

Always use VPN such as ProtonVPN

disable iMessage and if possible use a VOIP service. Only use messaging apps like signal, or protonmail for emails

At home set up a vpn through your router and use a proper firewall service such as pfSense. Setup a DMZ to separate devices from your home network