I am currently playing a Level 10 Twilight Cleric. It is indeed strong. But I've learned that there isn't a lot of variety in how the fights go. When in the fight, my spell list is effective, but limited in scope. The buffing is the priority, and that feels passive, so you don't feel like you are taking the fight to the enemy. Also, the Twilight Cleric really wants to go first in a fight, so others can get the temporary hit points before they get hit. If I go last as the Cleric, my allies are often getting hit before my Twilight Sanctuary goes up.
- 1st round Action: Channel Divinity: Twilight Sanctuary. It's an action so you don't also get to attack on the first round, unless you want to concentrate on a Spiritual Weapon or something (which I don't usually do, as I prefer Bless). If you don't have the Channel Divinity ability, you'll be functioning like a normal cleric for the fight. But with 2+ uses per day, recharging 1 on each short rest, you'll always have it for 2 fights, usually 3. I will say I've never had to consider using Channel Divinity for any other effect. Twilight Sanctuary is too good to pass up.
- 2nd round Action: This depends on the difficulty, type of enemy, and expected duration of the fight. If you are fighting a solo monster, Bless helps your allies really well with bonuses to attacks and saves. If you have 3rd level spells and you are fighting a horde, Spiritual Guardians is amazing. Both are concentration effects, which matters. At 9th level, I was able to use Circle of Power when fighting a scary Legendary monster, and it was an amazing feeling. I've never played a paladin at a high enough level to use the spell, and Twilight Clerics cheat it out at 9th level.
- 3rd round Action: Was the enemy able to get in some early hits or debuffs on you or your allies? Heal them now, otherwise use your preferred attack, whether a weapon, cantrip, or a bigger spell like Guiding Bolt if needed. I keep my higher level spell slots open for bigger heals or Spiritual Guardian uses, and use mostly cantrips or weapon attacks, as I trust my allies to burn our enemies down.
The fight is often halfway over at this point, but at this point you are plinking away while trying to keep your concentration going.