why does thunderbird not work with outlook.com or icloud.com?

Thunderbird works just fine with both of those providers, but and this is a big but. Third party software like antivirus products routinely block account creation. My guess is you are either using a third party antivirus instead of Windows defender, or one of the popular VPN products which appear to have all sorts of issues with email, and email providers like Google have all sorts of issues with them. Let's start simple. Is Thunderbird telling you the settings for outlook.com have been found? or is it probing for them? Frequently firewalls present a problem so Thunderbird simply can not look up it's database on the internet. The settings for icloud are here https://autoconfig.thunderbird.net/v1.1/icloud.com and outlook are here. https://autoconfig.thunderbird.net/v1.1/outlook.com So the issues are not that it does not work, even if it is not working for you.