He wouldn't lose much, since he can infinitely twin necro cantrips, and twin many 1-5th level spells every single day. But if you're looking to specifically emulate Saitama, then your build does a pretty good job!
I like the idea of Feinting Attack being "He looks like he's completely open" or "He looks like some random guy" like people say about Saitama.
Cleric's Reaper
At 1st level, you learn one necromancy cantrip of your choice from
any spell list. When you cast a necromancy cantrip that normally targets only one creature, the spell can instead target two creatures within
range and within 5 feet of each other.
It's pretty situation, 5ft only is too limited.
Look, the One Punche Man can cast It with twin spell for 120ft range without range of 5fts and still apply empower spell.
At higher levels, the One Punche Man is just stronger, Simulacrum, Flight Speed, Unearthed Recovery, Metamagic, Cleric spells, sorcerer spells and a infinite better attack rolls, counterspell. Anyway.
I will admit, a cleric inflict wounds hits hard if It hits, but the idea here is high chance to hit and high damage.
About Saitama.
Oh thanks, Feiting is really fun ("He looks like he's completely open" or "He looks like some random guy") and next hit is One Hit K.O. is fun!