What is most accurate way to test wifi connection strength in different areas of a building?

I am trying to compare different set ups to see what provides the best wifi coverage in all areas of a building.

Since using something like fast.com has too many variables, and not really what I'm looking for, I am wanting a way to view just wifi strength at a certain spot in the building. And then go back to this exact spot connected to a different brand of mesh system and see what I get.

Would using a program on the same device each time to view the connections strength in dbm be the best option for me?

Thanks