Are the boxes numbered wrong on the TurboTax form W-2 G?

You are trying to enter a W-2G as a normal W-2 from an employer.   You are in the wrong place.

Gambling

To enter the W-2G  or other documents For your Gambling winnings--

Go to Federal>Wages & Income>Less Common Income>Gambling Winnings

You can enter your winnings, and then keep clicking through the interview to enter gambling losses.

https://www.irs.gov/help/ita/how-do-i-claim-my-gambling-winnings-and-or-losses

Gambling winnings are taxable income.  Losses are an itemized deduction.  If you do not have enough itemized deductions to exceed your standard deduction, your losses will have no effect.

https://blog.turbotax.intuit.com/income-and-investments/how-are-gambling-winnings-taxed-8891/

2024 STANDARD DEDUCTION AMOUNTS

SINGLE $14,600    (65 or older/legally blind + $1950)

MARRIED FILING SEPARATELY    $14,600    (65 or older/legally blind + $1550)

MARRIED FILING JOINTLY $29,200    (65 or older/legally blind + $1550)

HEAD OF HOUSEHOLD $21,900    (65 or older/legally blind + $1950)