That would work for the situation.
This would need to have a permit to install this type of unit.
It will be mounted next to your existing panel and the critical circuits would have to me moved from that panel into this one permanently.
Not a big deal but added costs of permits and electricians will be required. Unless you have the knowledge to DIY, but the permit will be needed either way.
I always tell customers the same thing.
The level of protection required should be based on your history of power outages and the duration of the outages.
If I lived in a state that now does blackout periods for safety reasons then yes i would go to great lengths.
If I was in rural areas where power restoration was not high priority then again great lengths.
The heart of the city where thousands of homes and businesses where restoration will be high priority, well maybe not so much.
I should have posted this instead of a product: