Reforming Alternatives to Incarceration and Sentencing to Establish a Better Path for Youth Act of 2021 or the RAISE Act of 2021 This bill modifies requirements and procedures related to the sentencing, confinement, and release of youth who are involved in the federal criminal justice system. The term youth means an individual who is prosecuted or sentenced for a criminal offense committed at age 21 or younger. The bill modifies federal sentencing options for youth, including by allowing courts to depart from the statutory mandatory minimum for certain nonviolent offenses, to reduce the prison term of a youth who has completed 20 years of the sentence, and to treat as discretionary a statutory mandatory life prison term. Additionally, it requires the Bureau of Prisons to separately designate youth correctional facilities, minimize contact between youth and other offenders, and establish programs regarding youth education, skills training, reentry, and mental and emotional health. Finally, the bill promotes reentry and reintegration into the community, including by providing an early release option for youth offenders who complete one half or more of their prison term and meet certain criteria; authorizing home confinement for a longer period of time; limiting the maximum prison term for technical violations of probation; establishing pilot programs for mentorship, government service, and animal service; and establishing pilot programs for diversion of high-risk, victimized, and primary caretaker youth.