Schanuel grew up in the South Florida city of Boynton Beach and attended Park Vista Community High School, where he emerged as a star baseball player.

He played three seasons of college baseball at nearby Florida Atlantic, receiving national honors as one of the best players at the amateur level.

Schanuel entered the 2023 Major League Baseball draft with consideration as a top prospect and was selected in the first round by the Angels with the 11th overall pick.

On November 13, 2019, prior to the start of his 2019–20 senior season, Schanuel signed his National Letter of Intent to play college baseball for the Florida Atlantic Owls.

[6] In his final year at Park Vista, Schanuel was batting .520 with 10 RBIs and 14 runs scored before the remainder of the season was canceled in response to the COVID-19 pandemic.

[2] Schanuel enrolled at Florida Atlantic University, 14 miles from his hometown, to play college baseball for the Owls ahead of the 2020–21 academic year.

He aided in an opening weekend series victory over the nationally ranked UCF Knights by going 8-for-15 (.533) with a home run and eight RBIs; he later was named Conference USA (C-USA) Hitter of the Week.

[2] He spent the summer with the Bethesda Big Train of the Cal Ripken Collegiate Baseball League, batting .333 with three home runs and 24 RBIs in 24 games.

On March 7, he hit three home runs in a game against the Florida Gators, the eventual 2023 Men's College World Series runners-up, at Condron Ballpark in Gainesville.

He made his professional debut that day, going 2-for-3 with an RBI double, a run scored, and a stolen base against the ACL Diamondbacks.

[18] He reached base safely in all 29 games he played, setting a franchise record and tying Enos Slaughter for the third-longest on-base streak to start a major league career.

[22] On MLB.com's 20–80 scale draft report, Schanuel received a 60 grade for hitting, 50 for power, 45 for baserunning, 50 for arm strength, 50 for fielding, and 50 overall.