Which I use for years, and just because of lack of a better alternative (minimal, OSS) I actually quite "hate" it.:

It has no rules, like "Allow a file with THIS name on THAT path", the biggest complain of every simplewall user is its biggest flaw and annoyance: It asks you a million times to allow or deny the "same" app, after its checksum changed. So all the Windows apps that auto update always pop up again and again.

A coding agent autonomously compiling and testing an exe with network access is impossible. I have to turn off simplewall, because it would constantly block the executable after recompilation.

I also easily recommend this one. And OpenSnitch on linux seems to be doing the same job, though the interface can be less friendly.

Simplewall is quite terrible, IMO. They still haven't fixed the painfully slow fuzzy search functionality for firewall rules.