Your cleric always knows every spell they can possibly cast, but they'll only have a limited selection prepared each day - that number will increase as you level; at level 20 it will be ~36 spells prepared, including domain spells. At level 10 it will be ~24 spells prepared including domain spells.
Im aware ...
When you see that screenshot i added, you can see that i was only talking about prepared spells ... also only level 2 spells ... not domain, not cantrips, not racials, not item-spells ...
I still believe that casting from spellbook, with additional sorting inside of spellbook is best way. :-/
Right now spells in spellbook seem to be sorted randomly ...
If they were sorting aplhabeticaly (or even better, by type like: "Healing / Buff / Debuff / CC / Dmg") ... and in at least two rows, where first row is action ... second row is bonus action.
It just seems to me like the the best (and honestly only good) option, since you will allways have problems with hotbar in this game, there is simply too much things you can have there ... this way you could have there only few spells you use the most (i mean why even bohter having Air, or Mage armor on hotbar, since you use it litteraly only once per long rest), and the rest could be casted from spellbook (aka. spells interface).
