“Gaon, is there a relationship between the work allowed on yom tov with the guarding of matzos as the Yerushalmi Betza 8:2 as discussed above?
“But if learn that yom tov you allowed to do work for food needs from cutting that the watching of the matzos would also be from cutting.”
I am not sure that is pshat in Tosfos – according to the Yerushalmi there is a pasuk and Tosfos just says pshat when…and then says another limud. See the very end. Also see the gemorah and Rashi in Pesachim 40A בצקות של נכרים it will depend in all shitos and the Yerushalmi can go by a diff shitah regarding Shimur Lishmah.
Also, see the Aruch Hashulchan (link below) who explains the shitos and has a total diff take on the sugya, he holds (see S 20) that according to the Rambam you need Shimur for all 7 days.