I'm just as confused here. The Gallery app in the Play Store isn't what you want. You should have been able to download and install the APK file I sent you earlier. 😭
I wnede up calling customer service and technical support did trouble shooting. They couldn't find the gallery app either. I have a faulty device and have to intiate a refund.
I don't have an S10 YET... If it has this problem when I DO get it, hopefully this weekend, I will go into Gallery in the Secure Folder and go into About Gallery, copy the exact app name and version number and try to search that. If not found in Play Store... I would go check in the Samsung Galaxy App Store.