Focus your negotiation on things, in this order:
RSU grant. More shares is a permanent increase across all years.
Sign-on bonus. Higher sign-on bridges years - where RSU vesting is light.
Level. If you're borderline L4/L5 or L5/L6, push for the higher level. The comp difference is \100$K+ per year.
Do NOT negotiate base salary. It's capped and barely moves.
Never accept the first offer. Recruiters build in room for increases. Accepting immediately leaves money on the table.