Have you thought of just triggering your default browser with http://, and if Chrome is essential for some reason for your NAS (I think the underlying web view is the same for Chrome and Safari on iPadOS), setting your default browser to be Chrome?
I just got home had a quick go on my iPad for accessing my router (similarly accepts HTTP only ), and googlechrome:// is registered to open URLs with HTTP in the Chrome browser, whereas googlechromes://, which is what you have above, is registered to open URLs with HTTPS. So, if you really need to force Chrome rather than using the default web browser and an http:// link, try removing the “s” from the schema you stated in your first post.