Posting from mobile so can’t add screenshot but it should be easy to recreate. Let me know if screenshots are required.
Unable to replicate this on iPhone 12 Max running iOS 15.5 and latest Chrome.
What exactly isn't working? For me I click the button, get a popup with options for where to upload from - photo library, take photo or choose file. From there I choose photo library and uploaded a photo no problem, get a preview below.