Maybe the essence of her nature or the nature of her spirit of essence was mysteriously, incorporeal present but only not in substance but still substantially in the mystical sense of a non-speculative compounded presence. Or not.
Ah, now you see, this is why we don’t go wandering off from established theology and terminology every 500 years.
Words mean things...and 1500 years ago Christianity was nearly ripped apart by a debate over this very concept of substance: is Christ the *same* substance as the Father or just a *similar* substance? But no, we just make fun of all that in this day and age.
If it will help, I’ll use littler words.
Christ ain’t just in the Eucharist, He IS the Eucharist.
And because she’s His mom, Mary’s sorta in it too.