Could you point me to an example of a case dealing with election fraud or mishandling that was decided on its merits?

I’ve not seen one. Every one I’ve seen was dismissed procedurally before evidence was ever heard.

I'm not sure if any complaint was dismissed solely on the basis of the evidence, and not also because the plaintiff also failed to do other things like show that the court actually had article 3 jurisdiction, but certainly many courts found the evidence and legal arguments lacking enough to dismiss the case, in addition to finding that it would independently need to be dismissed for other reasons.

For example, see section F starting on page 22 of this ruling https://www.courtlistener.com/recap/gov.uscourts.azd.1255923...

The legal arguments being so bad that they failed procedural is not a defense for the Trump side, it's a demonstration of how badly they are failing to make a case at all. The easiest part of an allegation of fraud is to not fail on procedural grounds.

Edit: I mean - actually - easier than that is not being so aware that your evidence is lacking that you try and claim a case is and isn't about fraud in the same oral argument - but that's just a particularly special brand of incompetence and flailing that I've never heard of outside of the Trump campaign lawsuits... https://lawandcrime.com/2020-election/hear-it-for-yourself-r...