Resting - bg3.wiki
A Paladin X/Warlock 2 will get a couple key invocations (like the devil sight trick) and will recharge their two highest paladin spell slots on a short rest, for divine smite or for whatever other purpose.
Oathbreaker Paladin/Warlock Multi-Class Build in Baldur's Gate ...
The Death Knight - Oathbreaker Paladin Warlock Multi-Class Build in Baldur's Gate 3 copy ... This tactic involves using your Warlock spell slots, which recharge on a short rest, to fuel your Divine Smites.
Can I use Spell Mastery, Expert Divination, and Mind Spike ...
You regain all expended Pact Magic spell slots when you finish a short or long rest.