To steelman it a bit they want two things:

* Remove support they are ideologically opposed to irregardless of merit. USAID is the most obvious example where many of the things it does/did are opposed to the political and religious beliefs of those involved in scrapping it.

* With the 'America First' agenda it reduces the scope of what 'national interest' is in terms of foreign policy so they want to force regional partners to take more of role. This is clearest at the moment in Europe but they'll be doing the same to everyone else (e.g. Korea with China/North Korea).

Broadly the administration is continuing along the Project 2025 path. So the end goal is a more distant America waiving nukes at China.

They're going on vibes - a general feeling of "I'm not paying for that!" International aid is in the expenses category, and it's not a payment to me, so it must be cancelled! It helps that Putin makes big "donations".

Never mind that just a few years ago we were talking about how China's belt and road initiative would help it take over the road and now we are cancelling the American belt and road initiative.

Never mind that America is only rich because of its worldwide influence.

a handful of oligarchs get unfettered control to the US in exchange for a withdrawal from international agreements. simple overlap with some libertarian ideology.

heavily funded by Russia, and to a lesser extent China.

same playbook that pushed Brexit.