Most annoying thing is how when you pick up items it takes your current hand slot, assuming I'm not doing it wrong.
I assume this is when you pick up a new 1x1 block, if you didn't have an empty slot in your hotbar, it replaces the currently selected slot.
I'm questioning if this was a good idea, but I'd like to know your playstyle first
Have you experimented with the lock icons under the hotbars?
How often do you press Q to clear the hand?
How often to you press mouse3 to quick-pick a block?