No, smooth limp mode mainly points to electrical.
Well you ruled out most mechanical issues. So fuel pump, injectors, spark, are in good shape. It doesn't rule out vacuum leaks though, in limp mode the car runs super rich and masks any leaks. It's mainly sensor and electrical issues now.
It's not exactly the maf though. Unplugging the maf forces the ecu into limp mode, it ignores most sensors at this point. If you really want to make sure, you'd need to throw your maf into another car or borrow one from a working car.