In my experience, if you are on the "wrong" side of a building, you're often out of luck as the only signals that can get to any ill-located antenna either are going to be hopelessly attenuated by the penetration losses from passing through the building, reflected off external objects in haphazard ways, or they simply get shredded from the unfortunate combination of whatever signal finally makes it to the antenna's location. In all, it's simply potluck for reception when you're under those type of conditions and I consider it to be
impossible to predict reception reliably.
My favorite "indoor" antenna is an outdoor antenna that is used indoors. Sometimes, size does matter!
Our ClearStream 2V is
my overwhelming favorite but it's not right for everyone due to its size and it doesn't meet your price point objectives.
In the inexpensive indoor antenna realm that I've tested, and I have tested most of them, there's a lot of junk and a few unrecognized gems. For the "thin" antennas, the best overall UHF performance is provided by our Eclipse, but its design isn't optimal for VHF and you do need VHF in Des Moines. Runner-up compromise candidates would not be the flat thin antennas available from any of the brands found in retail stores, you'd have to order it. You can keep your existing amp, it's likely good enough for general purpose use. I'll send you a private message with my suggestion, please keep its identity private. If you go that route, let us know how it turns out.