Chain drops off outwards betweeng plastic guard and last cog on crankset
The front derailleur needs to be correctly adjusted for height, rotation and then for the H limit screw adjustment/cable tension
There is a good guide to the procedures here
https://www.parktool.com/blog/repair-help/front-derailleur-adjustment
I would also strongly recommend that you review the Shimano documentation. https://si.shimano.com/#/en/DM/GN0001
The front derailleur helps keep the chain on the largest ring, so if it's not properly adjusted it's not unusual to fall off.