The reason certain fingering is recommended (or suggested) is that it sort of works generally.
When you consider certain notes played in sequence, place your hand over those notes, at least the first three. Bear in mind that the next one in the series will probably need thumb again, in order to reach the topmost note in the second octave, usually with the little finger. This is all for r.h. of course!
So with your example of Em, r.h.1st inversion, the notes are GBEGBEG. It makes sense to start with thumb on G, and expect to move that onto the following G. So you can work out which of your fingers are most comfortable and efficient on the other white keys. Thwe do the same procedure for l.h.
That's part of the practice routine for a piano player - sorting out which fingering is best. Don't rely on complete strangers telling what is best - I could say what's best for me, but why should that automatically be best for you?