Standing in civil court means you have (allegedly) suffered some injury. If we have an ineligible President, we've all suffered, so we should all have standing.
Next you must have sufficient evidence to so that there is probable cause to believe that you really did suffer the injury and the plaintiff caused it. Not proof, just some indication/probable cause to believe
Then you can get the court to grant access to more and better evidence.
But these cases have never got beyond the standing issue and into the evidence. The standing issue has been used to block access to the hearing and presentation of evidence. Evidence has been submitted, but in effect the courts never looked at it.
In your example, you might have some indications, more than mere "thinking", such as sudden change in lifestyle with no visible change in legitimate income. That sort of "evidence" is used all the time to obtain more detailed records. If you were alleging the money was hacked out of your (and others) accounts, then that increase in lifestyle, along with a simultaneous "leaking" of money from your and others' accounts would be sufficient to obtain the records of his account activity. Now it might be that your neighbor just inherited a pile from a maiden Aunt you didn't know about. Fine, he was wasn't convicted, and that evidence served to exonerate him. OTOH, there could be mysterious "deposits" into his accounts, which matched the "withdrawals" from the others, and then he'd be in trouble, wouldn't he?
I think you’re confusing civil and criminal proceedings.