 If you liked
Mushoku Tensei: Isekai Ittara Honki Dasu
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 ...then you might like
Isekai Tensei Soudouki
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Both are reincarnation stories with similar atmosphere. They both feature comedy, adventure and magic and have a child genius as the protagonist.
Honestly, I think that 'Mushoku Tensei' is the original otaku reincarnation into a new world of sword and magic [from my perspective], and 'Isekai Tensei Soudouki' is the same, but with a samurai personality included.
Both have:
-Multiple love interest
-Swords and Magic
-Reincarnation trope
-Genius MC
-Comedy
If you like one, you will definitely like the other. [Also, please read the novels]