/usr/pgsql-10/bin/initdb --pgdata=/var/lib/pgsql/10/data-1
You may want to stop reading and start testing. Opinions are everywhere, but all of the mentioned products work correctly for their designed purposes (as well as for many purposes for which they were not designed). I'm voting to close the question as off-topic, as the question is essentially seeking product recommendations and design suggestions... and there is no objectively "correct" answer.
Have you looked at CloudFront? It seems to do much of what you're depicting, minimal config required, and only charges for bandwidth -- not storage -- so the size of the cache doesn't matter. Since you appear to be unfamiliar with exactly how to engineer this, it might be a better option. Google Cloud CDN and CloudFlare are similar services