I used to own a 2021 Mazda 3 hatchback that I bought brand new in March 2021. I owned it for about 1.5 years before selling it. My notes from owning it:
-Perfect blend of sporty and comfortable. I loved the seats and seating position in that car. I could drive it all day, but it was also fairly fun on a back road.
-The powertrain was wonderful for commuting! Very torquey motor and the transmission was pretty intuitive for a 6AT slushbox. Whenever I put my foot down, the car did exactly what I wanted it to do.
-The blindspots on the hatchback are horrendous. I was disappointed that Mazda prioritized style over visibility. For reference, the sedan's visibility is much better than the hatch's.
-The back seat and trunk are much smaller than you would think for a hatchback. I was coming from an FK8 Civic Type R (long story- it hurt my knee to drive), so I was shocked at how much smaller the Mazda 3 is in comparison to the Civic. They're supposed to be competitors, but inside, the Civic felt like a substantially larger car- massive difference in back seat space and trunk/hatch capacity.
-The doors have that thin, tinny cheap car sound and feel when you close them, but the rest of the materials inside the cabin felt very premium. It felt nicer than quite a few "luxury" cars I've driven over the years.
-Mostly city commuting, I think I was getting somewhere around ~29-30mpg. For an AWD car with 300 ft-lbs of torque and only 6 gears, I was impressed.
-******The car burned oil, brand new******* Yes, I followed the break-in period instructions. I think the first time I received an "add oil" message on the dashboard the car had ~3000 miles on it. It would proceed to burn about a quart of oil every 3000-3500 miles throughout the duration of my ownership. For a modern, brand new car, this was absolutely not acceptable to me. I never brought it up with a dealership (probably should have). Searching the internet led me to discover it was a fairly common problem... I'm pretty sure the culprit is supposedly the valve stem seals. I heard Mazda might have upgraded them/fixed the problem the following year.
-When I bought the car, no one was buying cars (seemingly everyone was terrified, hiding in their basements). I'm pretty sure I bought it brand new for somewhere around ~$29k or so (it was the "base" model Mazda 3 Turbo, which was still fairly loaded in my opinion). 1.5 years later, when the market spiked, I sold it for about the same amount of money I bought it brand new for.