I’m sorry, but I don’t have a lot of confidence that the OP has the trouble shooting skills to figure out what’s happening. As I understand it, new purchase of Conti GP4S tire, new tubes, gets a flat. Fixes, quickly gets another flat. That right there could just simply be bad luck, but there might be other issues related to not knowing how to deal with it. Is there a possibility either flat is a pinch flat due to too little air pressure ?, Yup. Possibly the tire was not carefully checked for the offending object after the first flat, resulting in the immediate 2nd flat - Yup. I’ve done that. Possibly not paying attention to where in the road you ride and are riding over debris a lot - Yup. Unfortunately, the entire post doesn’t give me a little of confidence that the OP will solve this easily and not sure making recommendations is going to help. Best of luck with it,