The following is the Dec. 2, 2022, Congressional Research Service In Focus report, F-35 Joint Strike Fighter (JSF) Engine Options.
From the report
The Department of Defense (DOD) is considering whether to upgrade the F-35 Joint Strike Fighter’s (JSF’s) existing F135 engine—the Engine Enhancement Package (EEP)—or to develop and procure a new engine for the aircraft—the Adaptive Engine Technology Program (AETP). Congress has long expressed interest in issues relating to the F-35’s engine. Section...
https://news.usni.org/2022/12/08/report-to-congress-on-f-35-joint-strike-fighter-engine