I live in a subtropical region, my winter is usually 40-50 degrees. I feel like a solid coop is going to cook my chickens in the summer
You are very smart to think this way.
Where, in general, are you located? You can put it in your profile to help people give you better targeted advice.
In mild-winter, HOT-summer climates Open Air style coops are especially suitable and hoop coops lend themselves to this kind of coop-and-run-combination. For 3 chickens a 2-cattle-panel hoop coop would be coop-and-run in one -- though if you *could* fit 3 panels in your yard it would be even better and you wouldn't have to build a separate run.