I have an investment loss for year 2021, but the entire amount is getting carried over to 2022. Why is there not any deduction for year 2021?

You don't have -3,000 on line 7?  What is the total net loss?

If you have a negative AGI or negative taxable income read Pub 550 page 66 and 67 on Figuring your Carryover.  So even though it shows it on 1040 it doesn't reduce the carryover to the next year.

http://www.irs.gov/pub/irs-pdf/p550.pdf

You can see it on the Carryover Worksheet. There is a Capital Loss Carryover Worksheet showing the carryover from the prior year and the current amounts.  Then there is also the Capital Loss Carry Forward worksheet showing the amount transferring over to next year.

In the Online version you have to save your return with all the worksheet as a pdf file to your computer to see the Capital Loss Carry Over and Carry Forward worksheets.

In the Desktop program you can go to Forms and find it in the list in the left column