Google interviews are the hardest in the industry, I recommend preparing for 2-3 months of you're a senior software engineer and at least 6 months otherwise.

Your recruiter should've sent you an email with all the subjects that form part of your interviews (are you doing only coding and leadership&Googliness or also system design? This is normally reserved for L4+).

Get "Cracking the Coding Interview" book/pdf and go through all of it, when you're okay doing half of the exercises of all chapters, get "Elements of Programming Interviews in Java" and again do at least half of all chapters related topics in your interviews (no parallel programming fortunately, it's too hard to do one of those in a 45 min interview). This will take you about half a year, then you can try going for the interview.

Another option if you know all topics already (or after doing the previous) is doing the Grind75 questions, they'll refresh you all the patterns that emerge in coding interviews in.. I think it's a max of 120 questions. You can tailor this with a slide on the website, but I 150% recommend you doing all problems in there.

Great advice!