Nah, it's not isekai, nor is it reincarnated in the future. He's the same person, but younger. It would be like falling asleep only to find out you're in caveman times again. Society looped back to before everything was so advanced either through loss of knowledge or loss of qualified people to teach.
After Reading: It's actually pretty good! I wouldn't say it's the greatest you'll ever see but it's a good 6/10. The white hair red eyes bs doesn't make the MC edgy(much) which was the main concern
*acts like a chad in front of Jack and Pickle*
*doesnt elaborate*
*leaves*