Refund taken in 2022 because I forgot to file a 1099 in 2018 how can I get it t back

This could not have been the first indication that the 2018 return was incorrect ... and if you fail to respond timely the IRS will correct the return themselves and put a debt indicator on the account and they took the 2021 refund.  If this did not fully satisfy the debt expect a bill to arrive for the balance due.  If you don't pay it then all future refunds will be taken until the debt is paid in full.

If the IRS did not take into consideration the withholding on the distribution then you may be able to send in an amended  return to refute their findings  BUT it may be too late to get any refund of a 2018 payment but you can try.   First I would get a return transcript & account transcript to see what the IRS has for the 2018 return then proceed from there ... you may also seek local professional help to formulate a response. 

https://www.irs.gov/individuals/get-transcript

please clarify what happened in 2018. a hardship loan is not income at the time of the loan. it would become income if you failed to pay it back and then the year it became income could be other than 2018.

It was not a loan if you got a 1099R for it.  It was a distribution.  And the taxes taken out was not the actual tax on it.  That was just estimated withholding like from paychecks.  You had to enter the 1099R and add it to your total income to calculate the tax on ALL your income.   The 1099R might push you into a higher tax bracket.  So the withholding might not be enough to cover the increase in tax due and any penalties like the 10% Early Withdrawal Penalty.

What code is in box 7 on the 1099R?  Did you pay it back  within 60 days?  And you had to put back the full gross amount including the taxes or the tax withholding becomes a taxable distribution.