On the terraria remake in pico8, the menu button has been used for inventory and holding that button showed the original menu. Maybe you can use that? You could maybe put also the restart button there! Also when you tap on the restart button it dosent do anything and you need to like slowly move the cursor to the button like on the PC you would with your mouse.
*Edit! I think you can like force 2 controllers? Idk, I just remembered how in Pico-8 DOOM you had like additional left and right buttons (or up and down? I think it was left and right)
*Edit! It's called Poom (the pico Doom game I was talking Abt)