American Tech Workforce Act of 2021 This bill eliminates the Optional Practical Training Program and modifies requirements for H-1B visas (nonimmigrant workers in specialty occupations and fashion models). (The Optional Practical Training Program provides an eligible F-1 student visa holder temporary employment authorization before or after completion of the student's studies, or both.) Under this bill, the employer must pay an H-1B visa holder the greater of (1) the annual wage paid to a U.S. worker who did identical or similar work in the two years before the employer's H-1B application; or (2) $110,000, with this amount to be adjusted annually for inflation. Currently, the H-1B visa holder must be paid the greater of (1) the employer's actual wage for similarly qualified U.S. workers in the specific position, or (2) the local prevailing wage for the occupational classification. The bill also removes a requirement for the employer to provide the visa holder with working conditions such that the working conditions of similarly employed workers will not be affected. The bill imposes limits on assigning H-1B visa holders to third-party work sites, such as limiting the visa validity period to one year if the visa holder performs any part of their assignment at a third-party work site. The bill requires the H-1B applications with the highest listed compensation to be granted before those with lower listed compensation.