The concept is simple. Which is good because it is easy to understand. You have a list of items and get them from the shelf within X time frame.
Execution wise, the player is spawned outside which slows down the pace of the game. Since it’s like a grabbing game. Why not have the player already inside of the store and you hit a start button. Like those Mr. Beast videos lmaooo
The items in the shelf could be organized more like in an actual grocery store that is separated by produce, diary, kitchenware, etc. Some of the items are very random which causes frustration and this is amplified by the short 60 seconds timer and lag.
I think the lag is due to the amount of duplicate assets that are in the game. Maybe you can scale the store down to make it smaller. You can still find items in smaller scale. Like referencing a page out of I Spy books. Which are confined in a [small area] but just has more visual noise to keep the eye for searching.
In comparison, your 3D store is like a maze and the player has to memorize the layout which is tough for playing first time.