You don't have to wait for 5 years to become an EB-2. You can apply for the green card in EB-2 the next day you join MSR/Google or any company. You can switch your job as long as you have a valid I-140 cleared by the employer. Although you would be applying a brand new GC at the new employer you will keep your priority date you filed with the first employer. Clearning labour certification and I-140 takes only less than a year.

AC21 is when you have an EAD and want to switch before 180 days of filing I-485.

And EB-1 is still an option, if you have a PhD. The chances with EB-1 is pretty high for you.