When doing a long research/digging session this is incredibly annoying. What happens is that you, on desktop, search for something, scroll to the bottom, hit "more results" and get a bunch more links. Then you accidentally left click on one to visit directly, instead of opening it in a new tab. Then when you hit "back" the SERP has gone back to only the initial results before expanding "more results," and you have to click it again. Of course you have also lost your scroll position, so it's easy to forget where you left off on the research.
I think this is why Google's SERP has a next button and the pages are numbered. It prevents this problem. But Kagi could keep the same UX it has, and just add a URL parameter like "?r=1" to indicate that more results has been clicked 1 time.
When I click back, the SERP should be restored to its state when I clicked a link, namely the "more results" should be expanded and the scroll position should match where I left off.