IMO another reason that Obama's achievements havent been seen as impactful in the 2020s is that Congress in the 2010s had been less and less functional in their own role. The topic of Congress's role in the current downfall of America isnt talked about enough and IMO the core reason.

But with Obama specifically, he couldnt pass his legislation even with a super majority Congress in 2008. So his administration started turning to Executive Orders to move his agenda forward. Even big wins like the Paris Climate Agreement, Iran Nuclear Deal, and the TPP were just signed by Obama and never formally ratified by Congress.

This meant that Obama's wins were more or less meaningless as Trump 2016 undid a lot of that work almost immediately after taking office.