You said that "missiles are not that effective for defense". If Ukraine is being invaded using e. g. lots of armored vehicles and you claim that missiles are not effective, what should they use instead? You only mentioned your "100 million bullets".

Adressing the current situation on the ground: So what? Infantry needs to be supported by vehicles, artillery and missiles to be properly effective. Zelensky was specifically asking for more Patriot systems (AA missiles!) just a week ago, they need them to shoot down Russian cruise missiles which are targeting Ukrainian infrastructure - yet you claim sending missiles is not effective for defense - huh?

If you're so convinced, please give me a concrete example of what missile that the US is sending to Ukraine is not effective or a waste of money.

^(And I don't think sending 100 million bullets would be worth it instead, Ukraine isn't actually short on mags. What they will need a lot of is AA missiles and artillery munition such as shells or GMLRS missiles.)