Welcome to the forum, as ex military myself I can say getting into or back into livestock is one of the better options with less transitioning problems than joobs with large staff numbers. For sheep in your area I would look into Dorper or one of the hair sheep breeds, less maitenence,, and there is no money in wool anyway. For longevity, depending on whether you want to run pure bred cattle, or crosses/composites, I would go for a british cross with a Sanga breed, probably easier to breed your own crosses either through AI or, buy a bull if any are locally available, look for Tuli, or Mashona, for fullblood lines, and Bonsmara, Senepol or South Poll as established composites. Dr Lukefahr sell some outstanding bulls from his ranch -
https://lukefahr-ranch.com/. Longevity and high fertility are features of African Sanga breeds due to thousands of years of natural selection and harder dentine in their teeth which results in less wear, inclusion as low as 25% makes a noticeable difference.