Family of 4 here with a Honda Jazz (aka Honda Fit in the US). Doing fine. Grew up in the states as a family of four and for most of my youth we had a Honda Accord - the early 90's ones that were smaller than a Civic is now IIRC.
Do you go on multi-day trips, where you need clothes are gear for everyone?
Do you have smaller children's car seats will take up 80% of the back seats?
Sometimes I bring a Brompton folding bicycle and a Thule Coaster trailer along with the kids when we want to go for a ride.
https://axkid.com/uk/product/axkid-move/ https://www.babyzen.com/