Ordered these once and they felt too fitted. Asked Vulpine to size me up. The logo on the back was also upside down lol. They ended up refunding me by accident, so I never bothered.
I use some flexible Uniqlo jeans. Not cycling specific but very comfortable!
I really like these - don't pay full price though. There are regular sales and I paid £45 for my last pair. They also have a slim fit Opus version.
https://www.vulpine.cc/collections/cycling-jeans/products/mens-omnia-cycling-jeans-indigo