I always keep a usb around with freedos for that reason. Works great and you don’t have to deal with windows

iCloud does have E2EE if you enable it

https://support.apple.com/en-us/102651

You sweet summer child

How are they going to get past my firewall rules?

You can watch rss feeds to follow all CVEs like Microsoft’s https://api.msrc.microsoft.com/update-guide/rss

NIST used to have an rss feed for CVEs but deprecated it recently. They still have other ways you can follow it though https://nvd.nist.gov/vuln/data-feeds

Or if you just want to follow CVEs for certain applications you can host/subscribe to something like https://www.opencve.io/welcome which allows you to filter CVEs from NIST’s National Vulnerability Database (NVD)