Someone would still have to take the step to remove him from the ballot or order his exclusion. Given the political climate it won't be congress, it won't be the executive branch, and it won't be the Republican party itself. Which leaves actors on the state level. Which comes with a whole bunch of problems of its own. If then, someone does actually give the order to remove him from the ballot the courts will become involved. They will pass an immediate injunction to halt the order for the removal until the case has been deliberated. The likelihood of this case being deliberated by the time of the election is slim at best. If they do get to deliberating it "early" we then enter a legal minefield as to how involved Trump was in the "insurrection" - which the courts will likely argue are part of an ongoing criminal case - so we have to await the results of that case. If that case, by some miracle, is done by the election, the issue will again find itself in the courts, and by this time the election has surely passed us by.
If against all reasonable odds the court proceedings of all these processes can somehow be tied up nicely by the election, the case will again be taken up by the courts and eventually make its way to the SC. That process will not make its way to the SC in time of the election, so it won't matter anyway , but let's pretend it did. In 1869 Salmon P.Chase, the sitting SC chief justice, issued a circuit opinion (not a SC opinion mind you) that set the precedent that section 3 of the 14th is not self enforcing, but would need congressional direction through law to be implemented. Given the courts composition, the political climate and what would be a historic decision of preventing a former president from running, the SC would likely lean on that, passing the buck to congress. Which then would do nothing.
However, even in the most optimistic scenario, a final decision in such a case - one that would likely just put the responsibility to Congress anyway - would be done long after the election is over. The only way to prevent the man from being president again is for people to vote for his opponent and to stop voting for him.
