I have an S9+. It updated to Android 10 on Feb 25 and a few days later my rear camera stopped focusing. It's just completely blurry all the time. Occasionally, it will focus on something very close up, but past that, it's just a blur. I've followed all the steps I can find online except for a factory reset because that's a nightmare. I've made sure the app is updated, force stopped it and cleared the cache, rebooted in safe mode and it's still blurry, cleared the app cache, and wiped the phone cache. This is extremely frustrating and surely there is some kind of fix for this glitch!
That happened to be the same date I received the Android 10 update from T-Mobile. Since then, I've had the same exact problem. The rear camera was working just fine before the update. A factory reset is NOT optional. Whatever was in this update just completely jacked the rear camera's ability to focus and they need to fix it!