Have you thought of paying just enough by estimates or withholding to avoid a penalty and let the government wait for your check?
For more information on if your refund was less than expected, please see the Help Article here. On this public forum, we do not have information about refund processing.
First, see if there is any clue as to what the IRS approved for your refund by using their tool at the IRS site:
When it pulls up your info, does it show on the left the amount of refund that they sent? If reduced, is any info provided?
If it was the IRS that reduced the amount of your Federal refund that's shown on your Form 1040, then they should send you a letter in about 3 weeks or so explaining why and what recourse you have if you disagree. Since no one knows anything about your situation, all TurboTax can do is tell you common reasons that "could" account for it. For example, in "some" cases it "could" be due to an offset, or it could be due to other reasons, such as a problem with various credits/stimulus payments, reporting/calculation error, etc.
FAQ: Why is my direct-deposited refund or check lower than the amount in TurboTax?