Don't let the "wording" in the media confuse you. You have to compare apples to apples.
The COLA increases your SS benefit by the applicable % - for 2021 that is an increase of 1.3%.
Monthly Part B premiums are increasing 2.7% of the average 2020 Part B Premium - it could have been a whole lot worse due to Covid-19 but the Spending Bill passed in Sept. 2020 held them down to 25% of what they could have been - with the government picking up the rest of the increase in cost. IOW, the Part B premiums could have taken the whole COLA without this action by Congress because of the Hold Harmless part of the Social Security (Medicare) law.
The Part B premium is increasing by an average of $ 3.90 ( From $ 144.60 to $ 148.50) - that's where the media gets the 2.7%.
I am reprinting only the Part B 2021 Premium announcement here - but the Press Release covers other cost announcements in the Medicare program for 2021 - so you can reference it for this info.
From the Link on Part B premiums for 2021:
Medicare Part B Premiums/Deductibles
Medicare Part B covers physician services, outpatient hospital services, certain home health services, durable medical equipment, and certain other medical and health services not covered by Medicare Part A.
The standard monthly premium for Medicare Part B enrollees will be $148.50 in 2021, an increase of $3.90 from $144.60 in 2020. Recent legislation signed by President Trump significantly dampens the 2021 Medicare Part B premium increase that would have occurred given the estimated growth in Medicare spending next year. Medicare spending is estimated to grow due to people seeking care they may have delayed during the COVID-19 public health emergency, availability of more COVID-19 treatments, and availability of COVID-19 vaccines (for which CMS recently announced that there would be no out-of-pocket costs for seniors).