Oneplus privacy? - eviltoast

Looking for some help with my Oneplus Nord CE3 Lite. I have had this phone for a couple months and looking to harden this phone make it a safe privacy friendly phone and avoid the constant monitoring and spying and being tracked and monitored. I want to limit the surveillance and monitoring best i can with this phone. Not interested in CUSTOM ROM and there isnt any available for my phone right now. So what is my options without that and how do i make this a safe phone?

Thanks