I've run into this 429 issue maybe because I try to optimize my search time by cmd-clicking links to open new tabs so I'm able to do it faster than a "normal" user would. I don't run any scripts or anything. Once it happens to me, clearing cookies and incognito usually doesn't work.

I found today that if you google a specific property, these pages are not bot protected like the home page is, and at this point I log in and start my search. Once I've logged in, I can now ingress via the home page.