Roof Vent Exclusion Cover - Recommendations?

Red squirrels entering through plastic roof vents.

Wanted to install hardware cloth and saw some pre-made ones. Any experience with a decent brand? I want something that won't have to be replaced, with wire thick enough to keep them out. Not sure what gauge, whether stainless steel is necessary or if galvanized is fine. Was looking at the ones at Home Depot (the brand is HY-C) and also the ones made by WCS.

Am I overthinking? Can these things chew through 18 gauge steel mesh?

Appreciate any help. These things are taking over my life. Thanks!