I was skeptical, but a fan does seem to help

I believe you might be correct that they are working on the towers and maybe brought up some n41 equipment. It does not have the reach or the penetration of the n71 given the frequency but yep the bandwidth would be awesome. The fact that cellmapper.net does not report all the various radio frequencies on the 5G is probably due to the database not being up to date. I found using my iPhone 12in field test mode was quite helpful. I used it with the router and confirmed the PCIs and radio signals it reported. Here the only 5G tower is like 5.3 miles direct line of sight or there is another over the hills and dales and through the trees off to the West NW but that one the router never sees. Living in the country or out close does have its limitations. I am pretty sure the router must respond to reflected signals in the house. Any other explanation just does not make sense to me.