Given the GOP doesn’t have much of a national game plan, and a good many of the GOP has distanced themselves from Trump (or at least haven’t openly supported his stances), I really don’t see how they take back the House. The voter fraud machine highlighted in California 2018 will prevent enough House seats flipping to the GOP.
Actually the GOP has some of the best candidates for the House we ever had, most of them very strong Trump supporters. Plus there are 30 Dem seats in districts that Trump won comfortably.
If Trump wins he’s carrying the majority of House districts. There is little reason for anyone to split a ticket.