What is the “popular vote?” You mean adding up the state-by-state votes which is a number nobody is trying to win?
And if we are talking about numbers that don’t matter, republicans won the Congressional popular vote four of the last seven times (by three million votes in 2022) and are on pace to in it again.
You can also look at the generic congressional ballot polling, where republicans regularly are ahead.
Don’t make assumptions about what non-voters prefer. Lower propensity voters lean right these days: https://hbstrategies.us/trumps-non-voters/ (“Within this lower propensity segment, the respondents favor Trump over Biden by 12 percentage points, 50-38%. The unit would prefer a Republican Congress by a 50-41% margin, and Republicans would enjoy the five point identification advantage.”).
And if we are talking about numbers that don’t matter, republicans won the Congressional popular vote four of the last seven times (by three million votes in 2022) and are on pace to in it again.
You can also look at the generic congressional ballot polling, where republicans regularly are ahead.