6 pellets a day pf any size is too much. I would say 2/day AT MOST pref.
I'm sorry -- but it really depends on the size of the betta/size of the pellets.
I feed all of mine bettamin, which is a larger pellet. My small girl gets 2 pellets 2 x per day, my stunted male gets the same.
My plakat is twice their size and is thriving on 4-5 pellets twice a day. He is a big, meaty fish and that's how much food he needs. 2 a day "at most" would malnourish him.
If the OP's betta is a large female and the pellets are small, I don't see anything wrong with that feeding schedule. If she was tiny, yes it would look like overfeeding.
And eating a bit of plant matter won't hurt your betta. Maybe she likes the taste. :)