Unfortunately there's a great many things wrong with Safari in iOS26. I and a few others have the same graphical bug that creates a random semi transparent square over everything when you try to type in a text field and the keyboard pops up covering said text field so you can't see what you're typing nor can you correct it when you 'think' you made a mistake. The whole extra tick arrow button to confirm text is completely useless as you can just click 'go/send' like before and I think it's related to that useless feature.
I did have a look on my phone for you but I can't really help you on your specific problem. I got round my issue by changing the tab layout to compact but then I get another issue that comes with that. Maybe try another browser until it gets fixed.