In iOS 13 (and prior, probably) there was a Camera setting that would “remember” how you had the app configured last time you took a photo. This was very handy if there are particular filters, aspect ratios, and other tweaks you typically use when shooting a photo. (These days, for example, I mostly shoot iPhone photos in Square ratio.)
After installing iOS 14, this totally changed. Camera would no longer launch to my previous settings. I found a preference that seemed to be the same as the one in iOS 13, but it didn’t work the same. Bottom line: To mimic the old behavior you need to turn on all three options in Settings > Camera > Preserve Settings. Seems like feature creep to me, but there you are, go forth and be happy.