Is this combined traditional IRA and Roth IRA maximum contribution of $7k true? Vanguard states that the maximum employee Roth contribution for 2024 was $23k?

It depends, your question combines information from different contribution limits. See the information below for the maximums of each type of contributions:

Traditional and Roth IRA Contribution Limits for 2024:

• The combined contribution limit for traditional and Roth IRAs is $7,000 if you are under age 50.
• If you are age 50 or older, the limit is $8,000

401(k) and 403(b) Contribution Limits for 2024:

• The employee contribution limit for 401(k) and 403(b) plans is $23,000.
• If you are age 50 or older, you can make an additional catch-up contribution of $7,500, bringing the total to $30,500

Here are some IRS resources for more details:

• IRA Contribution Limits
• 401(k) and 403(b) Limits

Vanguard was referring to a designated Roth account in an employer plan, not to a Roth IRA.  They are two different types of Roth accounts established under different sections of the tax code.