My thought is pinch flats from under inflation. Bite the bullet, get yourself a Topeak Joe Blow floor pump. They're bright yellow. Pump your tires to the high end of recommended. The JB pump is set up for presta or schrader valve stems. It goes to 160 psi, I think. Then get a Topeak Road Morph g frame pump. They're like a mini floor pump. They come with directions to make it for schrader or presta. 125 psi. Check your tires carefully by rubbing your fingertips around the inside of your tire after flatting. That will tell you where the puncture is coming from if your finger snags on something. A pinch flat has a signature that varies slightly, but it's obvious when you've seen a few. Others will chime in with more and better info. Again my educated guess would be pinch flats from under inflation. Good luck and stay with it. 👍