Apple's apps bypass firewalls like LittleSnitch and LuLu on macOS Big Sur

For anyone that wants to switch to Linux and retain similar functionality as this firewall app, there is this: https://github.com/gustavo-iniguez-goya/opensnitch

There is another - and I'd argue better - alternative for Linux and Windows:

Portmaster by Safing https://safing.io/portmaster/

Not only is it an application firewall, but also gives you DNS filtering (ie. Pi-Hole basics) and DNS-over-TLS.

Full Disclosure: I'm one of the founders.

But has it added pop-up per-app (and then per domain/port/ip) block/allow functionality in the Linux DE GUI yet? Thanks to your whole team for the awesome work.

This is already implemented, but was broken during an important refactor. We hope to fix it soon.