Just a suggestion. Spells without cooldowns can be "ported" into 5E as cantrips
For example, the hydrosophist(
https://divinityoriginalsin2.wiki.fextralife.com/Hydrosophist+Skills ) could be a subclass for wizards and sorcerers, using int for wiz and cha for sorc, having access to "dos1/2" style spells adapted into 5e, Spells with no cooldowns can become cnatrips, spells with longer cd's, adapted into higher tiers of spells, for eg Ice fan can become a 3rd tier spell. And as suggestion for Hydrosophist, I would say the following class features :
For Wizards :
- Level 2 : Hydrosophist Savant : The gold and time you must spend to copy any spell with "cold" or "water" spell into your spellbook is halved.
- Level 2 : Enhanced water magic : Every single spell, including cantrips with "water" or "cold" descriptor has +2 damage per hit dice. Eg - Cone of cold would deal +20 damage and frostbolt +2/4/6 at lv 1/5/11. You can't learn spells with "fire" descriptor and to use a spell scroll must pass a DC 15 check. If fail, you take d6 damage per spell level.
- Level 6 : Once per long rest, as a bonus action, you can remove the immunity or resistance against cold from a single enemy. in 18 meters from you.
- Level 10 : Enhanced water magic : When you cast Ice Knife, Ice Storm, Cone of cold or Summon Elemental(Water only) they count as being cast at one slot level higher than the one you actually use
This last feature took shock arcanist from Solasta as inspiration. Sorcerers would get the features as lv 1/1/6/11.
And this is only one suggestion.
Warfare can be a fighter/barbarian subclass
