I'm a freshman who is taking two courses (not prereq) that I am in danger of getting an A- (though I might get an A). Would taking a P look like a C if I have a 4.0 (mostly A+'s) for the rest of my courses? How would it impact my app? One course is an upper div math course and the other is a programming course.
It will impact your application exactly like a C would -- probably not at all since it's only two classes, but your 4.0 will definitely have an asterisk next to it. What is an adcom supposed to think? That your Ps are also As, or that they are the lowest grade possible? If they are conservative, they will assume the worst. This should be obvious to you!
The assumption is NOT that your P is just like all of the other grades that you didn't mask -- they assume you are hiding something (because, after all, you are!), and you would be very foolish to hide A-s because you think you are gaming your GPA to maintain a 4.0. Adcoms are not stupid, and this (taking classes P/F to hide less than desirable grades) has been going on long before COVID.