I have exactly the car you're describing.... Blue '21 6-speed. I still have less than 5000 miles on mine. I like it.... I think the FA engines will prove more durable long-term vs. the EJ engines but I am basing that on every STI owner I've ever personally known needing a new engine at some point, including one at just 19K miles. I chose the regular WRX specifically over the STI just so I could get the FA engine (and saving $10K was nice I will admit). I picked the base model so I could get cloth seats (I hate leather seats) and because I didn't want a sunroof. My only real complaints are the brakes (adequate at best; there is a reason people upgrade to the STI Brembos) and the shifter (it's clunky). It always takes me a bit to get used to the shifter each time I drive it; why they can't make a precise and crisp shifter like, say, every Honda ever made is beyond me. Some people complain about rev hang but I think that seems to be mostly gone by about the 2020 model year or so - compare a 2020 or 2021 vs. a 2015 and you will see the difference. My 2021 is just like the 2022s I have driven.
Mandatory mod list: Enkei wheels, Borla catback exhaust, IAG AOS, moderate window tint, OEM Subaru fog lights, 2" hidden hitch for my bike rack.