Ask HN: Why is opening a new window in OS26 Safari so slow this week?

Something unusual has happened. I can no longer instantly open a new safari window (I use new windows, not tables, I dislike tabs, don't judge...)

Anyway, back to the unusual. To get an instantly opening window I have to open a New General Window (command, option, shift, 2). Pressing command N opens a new personal window, which takes 2 seconds on an M4 Max. This is madness. I don't ever remember configuring a personal browsing window and I can't change the default behaviour.

What is going on behind the scenes and are Apple engineers using some kind of work around to this infuriating behaviour?

nb. I will not change my behaviour to using tabs.