I'm looking for a reincarnation novel with childhood included so it isn't just there born then it stops and continues 20 years later into the MCs life
Desolate Era,nine cauldrons,and in this each tome few years in childhood very interesting Mushoku Tensei - isekai ittara honki dasu
Two have already said Mushoku Tensei, so I add Bocchi Tenseiki. Also Maken no Daydreamer, but the chilhood "arc" is just the first few chapters, before advancing to late teens.
No fatigue is still in childhood period, or rather, it should be call newborn period. He currently look like 4-5 years old kid though.
Isn't that the case in most reincarnation stories? At least I don't remember a case where it directly skips to said person being an adult.