I would call these three things "readiness", i.e. you have to have them to be ready to fight. personnel costs also include retiree pay and benefits.

Procurement, i.e. buying more munitions and R&D are about 33% of the budget together.

big problem with trying to buy more munitions is that the money is not appropriated by Congress and i think they just went on recess again. the President can jump up and down and do cartwheels about how he needs more missiles but nothing will happen until Congress appropriates the money. He can have his undersecretary say "you have 21 days, we mean it!" like he just did. he can announce $58b purchases. None of that matters until the money is appropriated; defense contractors won't assume the risk. I want to say it has been some crazy number, like 18 years, that Congress has failed to do a normal DoD budget on time that is two years out as required by law. that failure by Congress is part of the shortage problem; without defined purchasing requirements the big defense contractors are loathe to invest in more production than the bare minimum required to field and recycle the missiles (the missiles go bad over time.)