Originally Posted by
supine
B-West is now open, however, it's a seating area with to-go food for those not-vaccinated or for those who doesn't have a recent negative test result.
Thus, the OP might still have luck entering the Senator Lounge near B43 with his Amex Platinum even if he's traveling in Economy.
I would highly suggest the OP to try his luck at B43 first before heading to B-West if necessary.