A TON of Safari tabs on iPhone disappeared

Within the last couple of days, I’ve realized that most of the 90 or so tabs I had open on my iPhone disappeared. They are not in the cloud; they do not show at all if I hold the plus sign button. They are gone. I have not synced the device to my Mac during this time.

This also happened on my iPad about a week or two ago, when about 8 tabs disappeared.

WHAT is going on with Safari and/or my devices?