This is largely incorrect. The USA has supplied Javelins steadily throughout the war, including 2022. Eg, the 1000 announced at the start of June that year [1]. Moreover they were far from Ukraine's only ATGMs in 2022. You're ignoring NLAWs and Stugna-P which certainly weren't 'spent in the first several months'. BGM-71 TOWs were supplied from the middle of the year.

The war in 2022 was primarily an artillery war. Drones were in use, but the dominance you describe came later.

1. https://www.defense.gov/News/Releases/Release/Article/304947...