Safari Signs Me Out Of Websites Randomly After Updating to iOS 18

I updated to iOS 18 on my iPhone 13 as soon as it was available. Fast forward to probably about a week ago, and I noticed as I was googling, that I was signed out of Google. As the week went on, I noticed more sites that I was signed out of, AND that after signing in, I had about 48 hour maximum before finding myself signed out again. I do not have Cross-Site Tracking Prevention on, and my iPhone is on the latest version of iOS 18. Why is this happening, and how can I resolve it?