My daughter was like this and she outgrew. One thing we did was we started with short drives with her alone in the car seat at the back. She used to cry, we played music, rhymes and gradually she adjusted.
I have a friend who's LO hated the carseat, and they found out it was related to tongue tie. Maybe your LO would like to go for walks in a wagon instead?
Highly recommend taking her to see a chiro who specializes in babies or an RMT who does infant craniosacral work. Often it is uncomfortable due to some tightness or stiffness….did ALOT for us with our daughter and now she is fine in the car seat!
Have you tried a carrier? That may help you transition to a stroller where she feels more comfortable. Because she is still strapped into a carrier but is on you (but looking away, and not at you) it may help her? Otherwise I think you just have to try and ride it out. If she starts to cry wait 2 mins longer each time before you take her out, kind of like sleep training but it will be stroller or carseat training. I tend to only take my LO in the car when she is tired(naptime). She always cries for a few mins and then passes out and wakes happy. I don't let my LO cry otherwise but when you are driving somewhere and you can't do anything about it, it helps to be persistent and show them you can't always take them out if they are unhappy.