This is my first review, so I hope it comes out alright

Do you remember when each anime season wasn't dominated by isekai? A switch was turned on at some point, and we get 10 or so every 12 weeks. That being the case we get a lot anime that feel pretty similar. Heck, sometimes I feel like I can nail the whole plot of the show by the first episode. So when a show does something to flip some of the typical tropes on its head, I think it's worth at least checking out, and I think Saikyou Onmyouji no Isekai Tenseiki does this.

Onmyouji doesn't completely reinvent the formula or anything. It's still your typical "strong guy gets reincarnated into NotEurope, and amazes everyone with his abilities." Personally I think a show like that is usually still fun, albeit generic and tired at this point. But I think Onmyouji does two things to freshen things up.

One is involved with its namesake. The MC, Seika Lamprogue, was previously born as a powerful Onmyouji or Exorcist in some sort of fantasy version of Japan. After some conflict he casts a spell that would reincarnate himself into anther world with his memories intact. Upon arriving in fantasy Europe, he doesn't possess the normal JRPG abilities that isekai protagonists and regular denizens of this world enjoy, but instead he still has this arcane knowledge from his previous life, and is apparently just straight up OP, but more than that, it's FRESH. Instead of casting fireball, or leveling dex, or whatever it is we're used to, this guy is placing curses, making thousands of flying paper dolls of magic, has knowledge about the fundamental makeup of organisms/objects, keeps a den of summons(some nightmarish) from his previous life, and reciting poems that I'm in no way qualified to say what they are, but sounds like ancient Japanese poems? The cadence he says them in has an air of mysticism to it anyway. Point is, I thought the show kept things interesting just because I wanted to know more about this supernatural system.

Another thing I found pretty refreshing, is that of course as an isekai protagonist, Seika is going to collect a bunch of ladies to hang out with, and they're all gonna fall for him before too long, but this guy, being you know, 40 or 50 years old mentally, just doesn't care for them romantically at all! He rebuffs all of their attempts, and treats them as almost students or family members since they're all in the teenage range. Which is great since each of the girls are pretty sweet, and I'd hate to see them taken advantage of like most anime protags would(ahem jobless cough cough). But without being bogged down by will they or won't they's, it lets the characters shine more on their own instead of love interest 1, 2, and 3.

You can make your own judgements on the story, music, setting and such, I just think a lot of people probably skipped this show, being one of the many generic looking isekai's out there, but I feel it has more going for it than meets the initial judgement.