How to convert App Inventor 2 app to Thunkable X

Is it possible to import or convert an AIA file exported from AI2 to Thunkable x?

No

Is it possible to: [AIA file from AI2] ---->[Thunkable]---->[Thunkable-X] ?

No. There are no extensions to Thunkable X.

I’m coming from App Inventor 2 myself. You’ll have to manually re-build the whole app here, I’m afraid.