Car seat

Have you still got the newborn insert in at the bottom? Looks like that might need to come out as her back is arched x

It’s a wedge underneath but everyone has told me that’s the last thing to come out but I feel like she doesn’t look comfy and the buckle to strap her in is really tight x

Is she over 60cm in length? If so, it comes out. That's probably why she isn't sitting right in it. I also wouldn't put the thick cardigan on her either and just replace that with a blanket when in the car so you can get her straps tight enough x

Just been reading the manual for your car seat- https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://dl.joiebaby.com/Instruction_Manual/GL/i-Spin-360/Joie-carseat-i-spin-360-instruction-manual.pdf&ved=2ahUKEwi5g-yy6aSJAxWjZkEAHcQsDXoQFnoECB8QBg&usg=AOvVaw2JNf7MScqxM0E46AJEC-OJ It says in there about recommending until 60cm x

Looks like it's common for people to struggle to get their little ones sitting comfortably in it from what I've seen online. Especially placement of the buckle and straps x

Hope you get sorted with it, I'd say there's a car seat safety group on Facebook but I've found it really unhelpful in the past, a lot of the members are very opinionated and unkind. I'd hate to thing I was giving you incorrect advice, but I'm just basing it off your manual and generic car seat safety x