Theoretically, yes. It's pretty unlikely.
The US alone currently has more than 2x the military expenditure of the entire EU. The US also has a larger GDP than the entire EU.
The US supplies the main bulk of Ukrainian military aid. https://www.ifw-kiel.de/topics/war-against-ukraine/ukraine-s...
The EU would have to make some very serious budgeting changes if they wanted to fill that void. A bunch of EU politicians would need to make the case for deep budget cuts, tax increases, war bonds, or some combination of those.