How long does it take for a new tech from l2 to l3 promotion in Google?

Hey guys, I am an L3 data center tech with 1.5 years of experience at AWS. I am expecting promotion to L4 in 6 months.

Recently, received an offer for L2 role in Google? The pay is around 30% more than my current pay. So was wondering, if I were to accept Google's offer, how long is it going to take for my promotion to L3. I would appreciate some constructive feedback.

Thank you!