The COLA also applies to federal pensions. Fauci retiring before Jan 1 means $25 to $30k pension increase for him. You will see a wave of USG retirements this year as a result.
I have seen estimates as high as 10%. Right now, predictions for the 2023 COLA increase range from 9.8 percent to 11.4 percent, based on the CPI-W current level (9.8 percent).