Based on extrapolating the vote in all the House races to the presidential election in 2020, the Democratic nominee will win the popular vote by nearly ten million nationally but the Republican nominee wins 274 electoral votes and the Democratic nominee 264.
In the 2016 presidential election, the Republicans won 230 solid red states and the House results show the Rs keep these states in 2020. In 2016 Democrats had 210 solid blue. There were 98 votes in close states (FL, ME, MI, MN, NE, NH, NV, PA, and WI).
Based on the House votes, in 2020 the Republican presidential nominee wins 3 of the swing states: Florida, Nebraska, and Wisconsin, for 274 total votes (230 + 29 + 5 + 10 = 274). So the D nominee wins the popular vote by a landslide and loses the presidency.