Cat, not eating before davening is an asmachta, one level below deoraysoh; the gemara says it’s based on lo sochlu al hadam, do not eat blood, which chazal darshen “do not eat before you pray for your blood”
The rambam makes zero mention of kavanah as a heter to eat before davening. The shulchan aruch harav introduces it, and of course his opinion is valid, but he does not say you could have a whole meal and eat whatever you want. Many chasidim are meikil on this to an extent, where they’ll have a small piece of cake or something…not more than a kebayah.
Chabad considering this a “minhag” is just ignorance, further proof thereof. But I’m sure you can rattle off at least a hundred sichos about elevated concepts that have basically nothing to do with your daily avodah.
As far as i know, the Lubavitcher rebbe encouraged women to learn all sorts of stuff, but stopped at gemara, because it’s against an open halacha in shu”a, that it is unequivocally forbidden to teach women gemara.
Do you learn gemara because the Lubavitcher rebbe said to learn it?