I think Democrats still take the House of Representatives, with a smaller majority. Some flips that were flukes and went back in actual 2020 wouldn't have occurred. For example SC-01, which only flipped because Trump decided to make down Mark Sanford and replace him with a nutcase.
The senate wouldn't have changed, though Republicans would have come out with 54 seats. I doubt Rubio would have appointed Beauregard Attorney General, therefore no 2017 special election occurs.
How much do you think seats like TX-7/TX-32/Orange County was inevitable due to demographic changes vs due to Trump realignment. I think while demographics did cause changes , I think without Trump those areas stay Republican till 2022/2024 so due to that I think the Republicans keep the House.
Now you could argue Democrats might be able to pull a 2006 with Rubio and win many WWC districts in 2018 to make up for that but I dont think that would happen due to polarization.