For years, my Reminders app does not properly sync with iCloud -- are "ghost" reminders my problem?

I have been having iCloud syncing issues with Reminders (and only Reminders) since the app upgrade many years ago. (I believe this was during the iOS 13 cycle.) My iPhone SE (as well as my iPhone 6, before it) syncs only occasionally (and rarely in full) with iCloud. Because of this, I'm unable to use Reminders on my other Apple platforms as they are always out of sync. For the past couple of years, I have used iCloud Reminders solely on my phone.

I've tried various corrective measures without success (including everything that Apple's support pages advise), but I recently noticed something unusual. I created a shortcut to try to assess the situation, which is as follows:

This shortcut will give me a count of how many uncompleted reminders I have, but that number is not consistent with what the app on my iPhone shows. For instance, as of today the app tells me that I have 383 reminders (in the All smart view). This shortcut, however, returns the number 400 as my actual count of uncompleted reminders. Over the course of a few months, this shortcut has consistently returned a count of 17 more uncompleted reminders than the app is showing.

So I created an additional shortcut to try to find what these reminders are:

This shortcut provides the full list of uncompleted reminders as a text file, and though laborious (due to my large number of reminders), I can go through it and find the ones that don't appear in the app. But that's as far as I can go. I search for them in the app on my iPhone (by name) and they do not appear. There is no search functionality for Reminders in iCloud.com, so I cannot find them there, nor do they appear in a manual search/scroll of each reminder list either on iCloud.com or on my phone.

I'm left befuddled. I don't even know if finding/deleting these "ghost" reminders would solve my syncing problem, but I have to imagine that they are somehow related to it.

I'm grateful for any thoughts or feedback. I'm willing to "reset" my iCloud reminders to a fresh status and rebuild them manually if such an option is available, assuming that doing so would fully and permanently remove all my iCloud reminders, including the 17 "ghosts" that are floating around in there.