We have the “axkid one2” for our first baby and it fits really nicely in our car - not sure on your make of car but I really recommend it as a seat 😊
Second the Avionaut Sky, we got it when my daughter was about 1 but I wish I had it from birth, bloody fab seat
Avionaut sky 2.0 goes from birth to 25kg so past 4 it’s a great extended rear facing seat 🙂 it’s also Swedish plus tested!