* What malware prevention service would connect to the IP of a !!mobile device??!! - none!
You are assuming that this whois lookup is reliable, which it very frequently is not. IP space is bought and sold all the time, and whois data may not be updated to reflect this.
* What has Amazon Technologies Inc. to do with all of that? - nothing!
AWS
I had just opened the page of the router in my LAN and nothing else.
enduringly long and high CPU fan load
There is absolutely no basis for your conclusion that these two things are related. You need real troubleshooting information here. As mentioned by myself and others, Firefox, and possibly other applications, may be making these connections as well. All of those suggested tiles, favicons, OCSP responder servers, and other resources have to be loaded from somewhere, and these are opt-out within Firefox, not opt-in.