This is just a small complaint I have, and if you decide to do nothing about it, it is completely fine.
When in battle, I sometimes want to check my character sheets/ items, sometimes to save time, sometimes to plan a battle strategy, as well as some other reasons. Unfortunately, you cannot access these menus in battle. I feel like it would be very convenient to be able to view your stats, and maybe others too, for a better way to battle. Just a suggestion! Overall, this isn't a problem, just a thing that would make the game even more smooth.