How big is your crate? Sized right, a dog crate should be just large enough for the dog to stand up in and turn around. They are supposed to be their small cozy den, not a play-pen. We used a soft-sided travel crate for our 10kg French Bulldog, and it fit fine, Though most of the time she just rode in the back seat, with a harness that snapped onto the seat-belt.
https://www.amazon.com/Noz2Noz-Soft-Krater-Indoor-Outdoor-Crate/dp/B000P9XMMY/ref=asc_df_B000P9TNLI/?tag=hyprod-20&linkCode=df0&hvadid=167132165277&hvpos=&hvnetw=g&hvrand=10020580579772288737&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9026839&hvtargid=aud-801381245258%3Apla-307860424479&th=1
https://www.kurgo.com/dog-harnesses/enhanced-strength-dog-car-harness/