I’m not disputing what you want to achieve, I’m just telling you that…
#1 - I don’t believe it has anything to do with Angular
#2 - As such, I wouldn’t remove the index from that file, particularly as I believe that means it won’t be included at all in your builds
#3 - You should be able to accomplish what you want entirely through that manifest.webmanifest file, which is officially known as a “Cache Manifest”
#4 - So I’d pull up the official documentation for cache manifests and see if the answers you’re looking for aren’t in there
If the cache manifest can’t achieve what you’re trying to do, then you’ll likely need to make modifications to the index file itself, as well as possibly the server, in order to set appropriate headers, cookies, unique and random URL parameters to spoof the browser into thinking every time it loads your index page that it’s doing it for the first time, stuff like that
There’s lots of methods for achieving what you want to do, and I DO believe that not only is Cache Manifest one of them, but also likely the easiest
If I’m wrong, and it’s not capable of this, there are many more known methods you can try out instead, but again, removing the index.html from your angular.json is NOT going to result in the behavior you’re looking for