I read @kPin’s thread about a chest GUI a while back, and although it was a good idea, this one would probably fit better with Bedrock Edition.
Idea: Have a “Favorites” tab in the item shop menu.
More info: This favourites tab will reside above the Blocks tab. It will include items that you have “favourited”, making the items that you use the most all accessible to you in one category.
At the bottom of this menu, there will be a button(or tab, idk) that says “Add Favorites”. When you click/tap on that, the normal item shop will appear but this time “buying” items would add them to the favourites menu. Exiting out of the item shop will exit out of the "Add Favorites "item shop.
Pros: Faster item shopping
Cons: Confusing for new players.
I do hope this gets added, although I can understand if this doesn’t if it takes too much developer effort.
p.s. i hit 1k likes so flex 
edit: To remove an item from the menu, open the Add Favorites menu and click on the item again.
