The Beginning After the End? I've read it before, but I'll have to brush up on it and get back to you. If I remember correctly, it might have been a little like Third Prince Elmer--but don't get your hopes up too high, since the author discontinued it. Have you tried RRL? That's where the Beginning After the End used to be. Also, do you have any details about what you specifically liked?
Unfortunately TBATE is western so it has a lot of elements that aren't really consistent with eastern literature (from what I've seen). It's a good story, but what aspects of it do you like? Expert transmigration stories are all over the place. Chaotic Sword God, Desolate Era, Mushoku Tensei (more thinking along the lines of Child Prodigy with these recommendations). TBATE is so good imo because of the author's writing style, nice comedic sense to it and a well built world. A lot of the novels on gravity tales aren't necessarily similar, but they're good (especially TMW/MW).
The fact it goes in depth on how the mechanics work in the world, the mc puts restrictions on himself, decent fights, the mc has the mind of an adult, and how the mc learns new ways to use his power and teaches others
Reincarnator is good if you're looking for "mind of an adult". Instruction is.. limited at best. Good world building, interesting MC.
Hmm, based on just that, try out... Tensei Shitara Slime Datta Ken Level 999 Villager Transcending the Nine Heavens World Teacher – Other World Style Education & Agent
I second World Teacher for, well, teaching. I'm not too sure about how far the translations have reached, but the main character spends several years teaching people. That's how seriously he takes it.