I would expect that your startup experience would place you well among a pool of entry-level candidates once you made it past the resume screening stage. Where the FANG position is going to help you is in getting past that stage. Fairly or unfairly, having a FANG position on your resume is kinda' like having a degree from an elite university in that recruiters will view your resume more favorably.
That’s a reasonable assessment. I worked at startups for 3 years before joining a FAANG company and they flat-out ignored my startup experience for leveling purposes, placing me as a junior engineer.