It boils down to managing those reaction abilities smartly during combat. The default settings can be a bit wasteful sometimes, especially when you're playing a paladin and divine smite triggers at less-than-ideal moments. The good news is you can really fine-tune this in the reactions tab of your character menu.

What works really well is setting divine smite to ask mode, which lets you decide when to use it after you've actually landed a hit. Even better, you can set different spell slot levels separately, so you're not burning your powerful level 3 slots when a level 1 would do the job just fine. Something interesting to keep in mind is that you can mix and match what's automatic and what needs confirmation - maybe keep those opportunity attacks on auto but save the important stuff for manual control.

Sure it might slow things down a bit with all the pop-up prompts, but honestly that extra control is worth it especially in those tough fights where every spell slot counts. You can always adjust these settings on the fly too, so don't worry about getting it perfect right away - just set it up how you think might work and tweak it as you go along.