i have lots of websites and numbers and phone gets hot easy i hear echoes when i talk on it, weird phone numbers software found jn my web data i have no clue what it is, apps turning on and off all by themselves! not receiving phone calls sometimes or text call long not showing calls going out, applications disappearing without me deleting them, getting locked out of my phone, passcode locks..
Best way to be sure you're free of such possibles. Reset the phone back to as delivered, and start over again?
If you have contacts and other (to you) critical info... backup those items first. You can use iTunes, but I've been using iMazing for the last few years. More flexible and in my view a better app. Once you've reset back as delivered, restore items you backed up?
Any apps/purchases from Apple-land can be downloaded/re-instaled for free.