From the earliest days of the TCG all the way up to Standard, there are several cards that allow players to draw up to a certain amount of cards. Examples of these cards include Steven’s Advice, Rocket’s Admin., Delta Draw on Holon’s Castform, etc. However, it’s very uncommon for a player to find themselves in a situation where they would opt to draw less than the maximum.
To help speed up gameplay, I think an “Always Draw Max” checkbox near settings should be created. Players who do not anticipate a situation where they might opt to draw less can simply check this box as a courtesy to their opponent. If they sense that this rare situation might arise, they can always opt to leave it unchecked or simply uncheck it.