Adult fiction SciFi-Thriller

Need help, saw a book that caught my attention and went back to buy it but it wasn't there anymore :(
here are some info I've gathered:

Fiction book
A man able to go back in time, remake important decisions
Creates two timelines, present and past
Guess: written fairly recently
From English speaking country

I'm sorry, I know it's not a lot to go on, I'll also try to find it again in other bookshops

Sounds a bit like Dark Matter or Recursion by Blake Crouch.

>2 jollyavis: it is unfortunately neither of these two, but thank you very much for answering

This may be Time Salvager by Wesley Chu.

>4 leennnadine: this sounds aweosme, though it’s not the one I was looking for. Still, thank you

>5 niklaus_wlsn: I don't know if this one is too old, but maybe All Our Wrong Todays?

I don't think all the details match but maybe the Timewars series?

>6 vorkosigan: that’s not it, but thank you

>7 humouress: it’s not it unfortunately, but thanks

About 20 years ago, Harry Turtledove wrote a pair of novellas called Forty, Counting Down and Twenty-One, Counting Up, which tell the story of a guy going back in time to change the past from the perspectives of his older and younger selves, respectively. I thought they had been published under one cover at some point, but can't find any evidence of that here or at ISFDB.

Here they are as an audio book:

https://www.amazon.com/Forty-Counting-Down-Twenty-One-Up/dp/B00188ABIO

And here's the Wikipedia page on the paperback. I think this is the cover of the copy I own...which is in storage.

https://en.wikipedia.org/wiki/Counting_Up,_Counting_Down

>10 DemetriosX: not it, but thanks it seems interesting

This sounds a little like "Pastwatch" to me (Orson Scott Card)?

Could be There Will Be Time by Poul Anderson. Might be a bit too early but it's worth a check.

>14 spaceowl: There Will Be Time doesn't match the summary. In particular, the past (or future) cannot be changed in the Anderson novel.

A long shot, but maybe The Revisionists byThomas Mullen?

The midnight library?

>18 ismellpaper: Touchstone: The Midnight Library