How do I prepare for a ~50% increase in salary in 9 months?

Currently L3 SWE at Google making $240K this year (would have been more but due to health reasons I couldn't deliver my best last year and got an MI rating). I have 2.5 YoE. I work on a product that has visibility every single year at Google I/O. My job isn't at risk and I'm aiming for a superb rating this year (definitely possible with my projects and Q1 performance so far) but I feel my compensation is a bit low. It wasn't low 2 years ago but it hasn't exactly increased like I would have wanted it to. I'm aiming for an L4 SWE position at another software company and want to ask about what my strategy should be and the theoretical max I can ask for. Can I land a $375K offer? What would the upper level of the L4 band be? I think it's worth targeting Snap, Roblox, Meta, Airbnb, Uber, and Netflix. On the HFT side I'm interested in Citadel's NXT program, Akuna Capital (Quantitative Developer), and Hudson River Trading (Algorithm Engineer). I had headhunters reach out to me for Citadel Commodities (bypassed online assessment) this year but I didn't follow through on the interview because I wasn't ready yet. What should my strategy be and how do I maximize negotiating and getting the best offer? Thanks in advance!