Treat yourself like your own mega Corp. Don’t give notice until you’ve already basically started at your new job (nowadays easier than ever), passed your background check. You don’t owe anyone anything, you have to look out for yourself, just like mega Corp is looking out for themselves. You can still be polite about it, but put yourself first always. Even if you sign and are employed at a Corp for one day and you find something better, never think twice about taking the better opportunity. Remember you are labor being exploited to provide the mega Corp with their multiples