i kinda chuckle to read that three clerics are seen as requiring some fourth person to jump in front of arrows for them. clerics have access to medium (or heavy!) armor and shields. bringing accountants in office casual slacks to wade through the Deadly Cave of Deadly Beasts ("ask us about our dental plan! (...we plan to bite you)") is a decision that natural selection could have adjudicated a while back.

also, even if this character is action-surging double spells at the top of each combat it shouldn't be too hard for the dm to either bait them into casting early on weak enemies or else surround everyone with undead that the clerics could then knock down just as flashily. or they could just short rest less. and none of that precludes the dm from saying, "look, multiclassing is optional and i regret okaying that. i'd feel more comfortable if your character were a single class."

i just get the feeling from this incomplete data that multiple people have having issues with expectations and outcomes.