Please lah, don't try to flip Android phones lah. 99% chance you won't be able to profit much. There is a reason why flippers only flip iPhones, not Galaxy phones.
For Pixel phones, usually it is not a good idea to be early adopter unless you really on teampixel. For me, always wait for discounts then buy. Don't forget Google is still feeling around on hardware so some Pixel models are essentially bad (like Pixel 4 and its battery). Read the reviews and then decide. If want to buy, wait for offers.
Only be early adopter for iPhones or Sony imo, because their phones have good QC before releasing to the market and they seldom have price drops in their official stores.