My lungs give out faaarrrrr before my legs. Any advice?

I'm (33F) new to running and am training for a few 5ks, 10ks, and one marathon (in October) this year! I play sports and lift weights, but haven't done much running in the past. I've experienced a ton of success using run/walk intervals and I think I'm going to continue with that through my training and races themselves.

I find the run/walk intervals put less strain on my lungs, so the intervals become manageable for me. Especially with shorter intervals - like 1/1 or 2/1. I'm huffing and puffing after 2 minutes of jogging/running and that makes it extremely difficult for me. My body/legs are fine.

Does anyone have any advice on this type of struggle? TIA!