Safari bookmarks disappearing after upgrading to macOS Tahoe. Description and solution.

I created a new folder in bookmarks and saved it in Favorites. Named it "Lawn Care". It is displayed across the top in the Favorites Bar. Populated this folder with 4 lawn care service websites, mostly so I could easily pay the invoices. The next day, one of the saved websites was missing. The following day, they were all gone. I deleted the folder, recreated it, and re-added the bookmarks. Same thing happened- they kept "disappearing". Then, I did extensive troubleshooting by creating bookmarks from my other 3 Apple devices (MacBook Air, iPad Pro, iPhone 15 Pro). These bookmarks always remained in the Lawn Care folder; only the MacBook Pro seemed to be affected. Next, I created a Test User and successfully recreated the problem- the bookmarks in my newly created folder disappeared once again. I presented the issue to 3 senior Apple advisors; no one could figure out what was happening. Shortly thereafter, I figured it out what had been happening. The Sidebar has a new feature in Safari 26.0.1 labeled, "Recently Saved". The website thumbnails are huge and I do not find this feature helpful at all. And there is no way to disable it. So I simply started to R-click delete these unwanted Recently Saved website thumbnails. What I didn't realize at the time was that this action also unknowingly deleted the saved bookmark in its respective folder; the thumbnail is not an independent element. Mystery solved. Without realizing it, I was deleting my saved bookmarks within the Lawn Care folder. Now, of course, this seems obvious. But even with screen-sharing on my MBP, 3 senior Apple advisors were unable to identify why the bookmarks had been disappearing. Worse yet, these very talented techs did not consider the possibility that Recently Saved bookmarks could be involved. I sincerely hope that sharing my experience with this issue helps somebody else. Hopefully, the Apple engineer elves will soon provide us with the option to "Hide" Recently Saved bookmarks in the Sidebar.