Hi there
Welcome!! You will find lots of great advice on here! Certainly saved my sanity on more than one occassion..
My first baby was like this, what I did was each day I would take her for a walk at catnap time. For me, this 30/45 min nap was almost the least important of the day as it was intentionally the shortest. So I would walk for around an hour or so, allowing for time for her to get off to sleep. It took a few days, but she got used to being in the pushchair and would drop off.
I also found that she preferred to sleep sitting up rather than having the chair in the laid back position (my son is the same). I think they both disliked not being to see what was going on fully.
Certainly both my two would conform to things once I kept on doing it for long enough!!
My son absolutely hates the car seat (4.5 months old) I try my best to time my trips with his nap times so he is very tired already and doesnt fight me so much on sleeping in it!
Hope this helps and let us know how you get on.
Take care
Lizzie xx