Took me four tries with times almost spot on the OP’s. 1:30.33, 1:30.28, 1:30.12 then a 1:28.12 this spring on a hilly course. 46 year old that just started running. Key for me in th last run was consistent mileage of around 55-60 per week. Long run pushed up to two hours at between 7:30-7:45 pace. Ran by effort so if I had to run slower I did but 8:00 was about as far as I would back down on long runs. Last few weeks I would finish every run at hm pace for 1-3 miles. Ten days out a hard eight miler at about 6:45 with no rest before. Finished last week with another sixteen miler and then tapered. I think getting to pace daily for the last few weeks and the eight miler continuous made difference in my last race. At mile nine I knew I was ahead of pace and went after it. Weather was perfect for me but this is how I did it.
Good luck, mileage will get you there with some faster finishes thrown in I think.