In 21, I had capital gains . I reinvested the tax due. In 22, I had capital losses and could not pay the 21 tax. Can I use my 22 losses to offset the 21 capital gains?

[rjs]

No, you cannot use capital losses in 2022 to offset capital gains in 2021. You have to pay the tax that you owe for 2021.

[DoninGA]

Capital gains and losses have to be reported on the tax year when the the gains and/or losses occurred.  Not on some future tax year.