Why to you think there would be a limit on wages earned ?
There is a max for box 3 Social Security wages.
For 2021 the max for Social Security (box 4) is $8,853.60 on $142,800 of wages (142,800 x 6.2%).
IRS W2 https://www.irs.gov/pub/irs-pdf/fw2.pdf
Instructions https://www.irs.gov/pub/irs-pdf/iw2w3.pdf
It is my understanding that if a value of larger than 999,999.99 is uploaded to the IRS, it breaks the system. Any number can be printed to paper with only the limitation of the print rendering software, but the concern is the back end of the information that is sent to the IRS. Can it accept a number higher than that?
OK ... the TT DIY program has a limit on digits (not the IRS) so you will not be able to use the TT program but if you are making more than a MILLION dollars on a paycheck why are you doing your own taxes ???
Your question was whether the IRS places a limit on how much income you can report on a W-2. Turns out you were not asking that. You want to know how much income can be entered using the software program. Since TurboTax is for do-it-yourself tax returns, it's pretty safe to assume that people with W-2 incomes over the amount you are worried about would not be using do-it -yourself tax software.