I'm making a thematic Paladin class for one of my players, and I'd like them to be a spontaneous caster with a thematically appropriate list of spells, but not all of the Paladin spells.

While I would prefer them to "Know All Spells" I'd also be willing to just prepare their list for them and tell them they can only cast those, if I can change how the number of prepared spells is calculated.

You can add additional spells to the subclasses spell list, but that is about it.

I'm going to add specific spells from a list I'll share with my player outside of DDB to the custom class. Thanks though! Wish we could make tweaks to the bases.

When I make homebrew subclasses for spellcasters, at the bottom there's something that says [Spellcasting Ability] (without the lines at the beginning and end). Maybe try setting that to what you want and see if that works?

I had a similar issue for my cleric — I wanted to take out some spells that were banned by their god. I couldn’t, so I just homebrewed copies with the same name, but “NO” next to it, so it basically acted as a reminder to not select those spells when preparing spells. Not the cleanest solution, but it got me an indicator in my spell list.