I have, but don't the Americans use Aces seats.
No, all 3 models of the F-35 use a MB seat - though there is a continuous and ongoing campaign by certain parties both within the DoD and US industry get the F-35A to switch over to a modified ACES seat.
The modifications done to the MB seat to remove the pilot weight restrictions and neck injury issues should have put those to rest - but I wouldn’t bank on it.