Remember: the EC vote is certified by the new Congress, whose term begins Jan 3. The Republicans currently hold the House and would certainly vote to install Trump in the event of a contingent election, but who knows if they'll still have control after Jan 3.
But if they somehow manage to delay the resolution of tight House races that would provide a Democratic majority beyond Jan 3, it might be possible for the Republicans to temporarily steal control. On top of that, if Republicans did have control they'd have to pick a Speaker -- it would not automatically be Mike Johnson -- in order for the Presidential certification on Jan 6 to happen, and that itself could be a huge problem.
In other words, unless the Democrats win back the House, with enough margins to be indisputable even in MAGA-Federalist-Society-controlled courts, it's entirely possible that all Hell breaks loose.