Hi, I think you are on the mark in looking for a non-GTX boot for summer. In fact, you may be better off with a non-GTX boot in general depending on how much rain/snow you get in winter. A non-GTX boot will breathe better and dry faster, but it won’t be fun if you are in a climate where you expect wet + cold.
As far as finding a boot style that fits you well, I would recommend someplace with a broad selection of hiking boots and with salespeople with some level of training. REI fits the bill here and I would recommend seeking them out, but you may have other local alternatives. You need to try a number of different makes/models side by side. Boot manufacturers use different “lasts”, so boots from different makers will fit different foot shapes better or worse - I think this will be equally important to finding a comfortable boot, as many manufacturers make Wide models. This is where someplace like an REI helps because they keep a lot of boots in stock. You should be able to try on a few different choices during your visit and hopefully the salesperson can get you pointed in the right direction with some educated suggestions,
Good luck in your search.