There's no single report summing this up, but here are a few article discussing European dependence on US arms exports

• https://www.vaticannews.va/en/world/news/2025-03/arms-imports-soaring-in-europe-sipri-think-tank-says.html
• https://en.hespress.com/105384-report-european-militaries-reach-60-reliance-on-us-weapons.html?print
• https://www.thehindu.com/news/international/europes-dependence-on-us-arms-rose-in-last-five-years-says-report/article69311997.ece
• https://www.sipri.org/media/press-release/2025/sipri-top-100-arms-producers-see-combined-revenues-surge-states-rush-modernize-and-expand-arsenals

The problem that Europe has is lack of access to cheap energy. They're now pretty entirely reliant on expensive LNG from the US, and industries things steel production, essential to the military, are incredibly expensive as a result.