Firewall vs Firewall off-no internet to application

Hello,

I have a question regarding the difference between what an application sees when they are denied via the firewall vs just removing the internet. Using AVAST Internet Security - paid version

I have a high end CAD program that uses a HASP Dongle. I think this is FLEX/LM FelxNet but not sure. I have privacy concerns with the company and what data they send outside so I have the program blocked via the AVAST Firewall. The program is very slow to load and stalls when licensing related features are accessed.

If I remove the network (unplug the Ethernet cable) there is no difference in performance. However’
If I remove the network (unplug the Ethernet cable) and disable AVAST Firewall the program is snappy, and runs as I would expect it.

In my limited understanding I would think removing Ethernet cable/firewall and using the firewall would look the same to the application. What else is the difference? Is there anything I can adjust regarding Avast FW to fix this?
Of course the software company just wants me to open the firewall, which I will not do.

Thank you

→ https://support.avast.com/article/25/ (Firewall FAQ)