I'm struggling to enter an RSU sale correctly. My confusion mostly comes from the fact that TurboTax doesn't ask me what the stock price was when I sold the RSUs.

stock price doesn't matter. cost basis matters.

the cost basis is known, Based on the number of shares you had to give up you can calculate the price per share

The stock price when you sold the RSUs is the price they sold for.  The sales proceeds.

RSUs are taxed when they vest. Income is reported on the W-2 and shares are withheld to cover tax on the shares. Nothing else is reported on the tax return until the shares are sold.

A 1099-B is issued when the shares are sold. The basis of the shares is the market rate of the shares at the time of vesting that was reported as income on the W-2. When the sale is reported there will be a capital gain or loss. If sold the same day they vest, there will be a small capital loss due to the sales fee.

You need to know how many RSUs vested and how many were withheld for taxes in order to determine your basis.

You should be able to find the grant information on your 1099-B form or your consolidated statement. If you can’t find this info, contact your brokerage or your employer's stock plan administrator.

To report RSU sales in TurboTax:

When you enter you 1099-B information you will be asked: 'Do these sales include any employee stock? This includes ESPP, RSU, RS, NQSO, and ISO' Say yes.

Then you will be asked 'What type of investment did you sell?' Select 'Restricted stock units'

Check the box that says 'The cost basis is incorrect or missing on my 1099-B'

Then select 'I need help figuring out my cost basis'