I don't think that's what cost them down ballot. I think down ballot in Red States is difficult and I think while some voters were happy to dump Trump, because they obviously realized he stands for nothing they stand for, they were not willing to dump voting Republican. So, that's a bigger fight than winning the presidency which we've obviously seen can shift back and forth based upon what are some slim margins. Trump barely won in 2016. Biden won a lot bigger in terms of voter turnout but will win by the same margin Trump did in the electoral college. 

The Georgia runoff is huge. If the Democrats can get those two seats we will have a fully functional government for the first time in years. If McConnell holds the senate...well...he will keep things stagnant and dysfunctional and do all he can to destroy anything Biden tries to accomplish.