They would live happily ever and after lol

^ Yupp

There's no what if if youre already living it. Petrification day was June 3, 2019 after all. Tsukasa and Gen would never meet the Trio. Senku would likely be working at J.A.X.A. or N.A.S.A either going to the moon or pursuing the same thing as Dr. Xeno, possibly work beside Xeno as a Colleague.

Taiju and Yuzuriha would be happily married and settled down with kids. As Taiju would likely get into something like Construction (Since he's muscley) And Yuzuriha be running a fabric/craft store.

Tsukasa would continue his career in the MMA.

Gen would still be a show man.

But then a rift in the space-time continuum appears, which shows the Kohaku, Chrome, Suika, Ginro, Kinro in the future wondering what is causing the rift and Senku will be horrified at seeing monsters. the universe would rip open and even the intervention of the Vice Presidential Action Rangers would be unable to keep the tear from undoing existence as we know it. Senku and the VPAR would then play Dungeons & Dragons for the next quadrillion years.

Uhhh wha?