And those projects will either never have Kavita+ features, or will die out because they do not get enough one time donations from people to keep up those features. The Kavita devs are litterally providing everything for free, other than things that cost them money monthly to run. You being but-hurt about that is nonsensical.
Windows Defender is actually quite good these days. The main reason an enterprise would use a 3rd party AV/Firewall would be centralized management of said av and firewall. If IT needs to install apps and make them work, they also need the ability to manage the AV/Firewall.