Hi Michele,
It is certainly a concerning and difficult position for you to be in.
To answer your question, if you cancel their homeowners (HO) policy to move to a Course of Construction/Builders Risk (COC/BR) policy, returning to an HO form later will subject you to new business underwriting. Given the location, this would likely trigger issues related to brush exposure.
On the other hand, a standard homeowners policy is not designed to cover active construction. It may contain relevant exclusions such as vacancy clauses and potential gaps in liability coverage.
USAA is a good company, I could see why you would want to keep the policy, just not sure if it’s realistic. Amir