JW wrote:

I'm currently running all the devices on the network at 2.4GHz. I'll
probably leave it that way as I think only my phone is capable of dual
band operation, and according to the Internet (so it must be true) 2.4Ghz
has better range and penetration through walls than 5GHz.

That's generally true, and if you're using 5GHz indoors it's usually a
good thing as it tends to keep everyone else's signal out (not that it's
so crowded to begin with, but usage is growing).