I've been using macs for 24 years with no spyware/adware or virus protection running.
No spyware/adware can be installed on your system without you using the administrators password.
You as the operator decide what gets installed by using your password.
In other words don't worry about anything, your a mac user now.
It works just like a toaster. You put a piece of bread in, push a button, and it makes toast.
it just works.
--Eric
😉