The Bulwark journalist A.B. Stoddard warns that if Harris wins in November, an "entire army of Republicans" is "ready to block certification of the election at the local level." Stoddard continues, "Their goal: Refuse to certify anywhere — even a county that Trump won — and prevent certification in that state election." A Harris victory could become a nightmare."
https://www.rawstory.com/maga-has-game-plan-to-halt-elections-if-harris-takes-lead-report/
I don't really understand this strategy. Let's say that several states don't certify at all. No electoral college picks.
On January 6th the President of the Senate shall open the certificates and count the votes. Nothing about missing states. The winner has the majority of the votes received.