One of the best ways to judge the political environment is through the generic congressional ballot. The generic ballot asks respondents some form of the following question: “If the elections for Congress were held today, would you vote for the Democratic or Republican Party?”
Democrats are ahead on that measure by about 4 points in the average poll taken since the beginning of Biden’s administration. That lead is about the same as the final margin in the 2020 presidential race (Biden +4.5 points) and the 2020 House popular vote (Democrats +3.1 points).
This tends to line up with what we have seen in terms of party identification from the average pollster: the Democrats’ advantage has been steady since the election.
Remember too that the 2020 polls tended to overestimate the Republican position. This means Republicans are actually doing better on the generic ballot now than they were heading into the 2020 election.