Help me switch

I plan to resign in March 2026. Currently I work in service based firm, I wish to switch to product based not faang based but something like adobe , optum etc. can anyone who give some tips, DSA I have not done much but how much is required , can I skip graph and dp. For service based firm I cracked it just by regular java spring boot questions. I will start preparation from now, hope 3-4 months is enough. I will have 3yoe when i resign. I know it's less experience but for product based its fine