Since America is so in love with car infrastructure, just turning open parking lots into covered lots would be more than enough.

Just converting all Walmart parking to covered solar would meet almost half of all US electrical demand.

4,070,000,000,000 kWh US electric use in 2022

Using 330W panels it would require 8,447,488 panels (4,070,000,000,000 kWh / (330W * 4 hours/day * 365 days/year)) which is 164,726,016 sq ft at 19.5 sq ft per panel.

Walmart has 4,612 stores in the US, averaging 1,000 parking spaces per store, and 180 sq ft per parking space (does not include driving lanes, end caps, etc.) giving us 830,160,000 sq ft.

You divided kW by W, so off by 1000.

Also doesn't count continuing to put solar on roofs.