It's not easy to remotely hack an Android phone without first having physical access to it or you downloading and installing something yourself. Have you changed the setting install from an unknown source to be able to install from outside the play store? Most likely it would be someone having access to your Google account or your passwords. Go to your Google account settings and remove all the logged in devices that are not the phone you're on. Then change your passwords and go through all of your Google account settings. Remove access to your account for apps you don't use anymore, etc.
I'm telling you from experience because I spent way too much time long ago doing exactly what you're doing now lol. And I promise you half of the stuff on your phone and how things work appear suspicious and odd, but it's all completely normal. Go Google hacking an Android remotely and read about it. Every single spy app will say spy remotely without having the device in front of you, but keep reading and you will see that "spy remotely" comes after installing an app on the target device. You are the best anti virus for your phone as long as you stick to the play store and don't even give anything the time of day that you aren't expecting or know what it is.
Download the app root checker in the play store to ease your mind about your phone being rooted. I can almost guarantee that if someone actually is messing with you then they are doing it through your accounts. Your Google account is the center of everything so if someone has your password they can get your location, what apps you're using, search history, photos, contacts, etc. Go through your accounts, review logged in devices and remove all that are not your current device. Change passwords to more complicated ones. You can check the integrity of your passwords through your Google chrome settings if you save them there. You can also run your email here
https://haveibeenpwned.com/
What gets people, got me too, is googling suspicious things you find in your phone and seeing multiple posts from other people claiming the same thing. It makes it seem more legit.