I have found a possible solution! I too have suffered with this forever. Now YMMV, but this was my setup and particular occurrence of this problem:
Devices (all on latest OS, always):
MacBook Pro 2019
iPhone 14
iPad Pro
I only saw ghost tabs FROM the iPad ON my MacBook Pro. I have tried everything, as you know, this problem is all over the internet in discussion groups.
I got to thinking, why would ghost tabs exist in iCloud, that don't show on the device when running Safari, that can be closed from other devices, but they come back again? And then I realized - I recycle my device names over the years! My convention is that I name devices after cities in Hawaii, and I have my favorites - so my iPad for example, is "Honolulu". But I have used that name before on other devices in past years. So I got to thinking, maybe somehow the ghost tabs are from a device "Honolulu" that used to exist, this "Honolulu" doesn't see it, but other devices do when data about "Honolulu" is pulled down from iCloud.
And then I thought of another theory - with nothing to do with recycling names - I thought maybe in my case, the iCloud tabs data is just corrupted somehow from some former OS version, and it can't be easily fixed (as we can attest). So---
I had previously turned off iCloud Safari syncing on Honolulu/iPad. I changed the name of my device to something entirely different and guaranteed unique for me ever - I named it "Basil" (Switzerland). I turned on iCloud tab syncing, it asked if I wanted to merge iCloud Safari data from the old device. It only allows yes lol (why ask)....so I merged. I gave it a few minutes to adjust to a new iPad name, opened a tab on there iPad, went to my MacBook Pro and bought up the Start page to see iCloud tabs on other devices, and the 2 ghost tabs were there. Darn. I deleted them from my MacBook Pro's start page entries for the iPad.
BUT - since then, it's been a solid hour, I have been bringing up different tabs on Basil/iPad, checking the MacBook Pro, and it's been perfect! I am thinking this might have fixed it, whether there was an old usage the device name or not - just change the device name to something you have never used. Maybe the ghost tabs got merged across, but then could be easily deleted (even though the did not show up as actual tabs on the iPad.)
So the bottom line, rename your device to something guaranteed unique in your Apple device history. You may possibly have to delete the ghost tabs one more time wherever they have been appearing.
See if it helps.... you know, I have never seen anyone propose this as a solution to this problem, so maybe....My problem is different than others, in that the ghost tabs showed up only on one device - some people see it on every other device. There could be multiple reasons for ghost tabs for sure, but maybe this helps someone? Good luck! I'll post back if it proves to not last for me.
EDIT/UPDATE: Never mind - old tabs have come back twice 😩😖😡😵💫