This is likely being downvoted because the US isn't donating weapons to Ukraine, it's leasing them to Ukraine in the same manner that the US leased weapons to the UK during WWII. The UK only finished repaying that debt in 2006.
"Any loan or lease of defense articles to the Government of Ukraine under paragraph (1) shall be subject to all applicable laws concerning the return of and reimbursement and repayment for defense articles loan or leased to foreign governments."
Can you provide a source for your statement that these were donations?
Most aid takes the form of cash for humanitarian support, ~disposing of~ donating old hardware to Ukraine, or a loan for the express intent of buying a modern system.
The vast majority of the "billions" given to Ukraine is made up of stuff that we actively are trying to throw away.
