With the way this place has been so disrespectful and ungrateful and ungracious toward their many employees who have given years of excellent work and who are now being shown the door, I wouldn't even worry about it, and I'd plan things out to my own best advantage.
I wouldn't put myself in the position of maybe or not being able to get paid for those last couple of weeks' work, because I wouldn't allow them to have that leverage. I'd keep what limited leverage I have, for it to work for myself! That means, I wouldn't give notice, I'd just keep working until my "buffer zone", and then peace out! This way, I'm in control, and I'd be paid up to and including my very last day of being "on the books" with Centene, because it would be very cut and dried, with no wiggle room for them to decide one way or another IF I should be paid for my last couple of weeks or not.
That would mean: when negotiating a start date with my new employer, I'd see if I could start at least 3 weeks out from when I'd received their offer. They probably wouldn't have a problem accommodating that, since giving at least 2 weeks' notice is standard.
Once I signed the new employer's offer letter, and received confirmation from them that it's a go, I'd then make sure that my personal email/contact info. was current/updated with HR, then get anything physical of my personal belongings from my current work location that I want to keep, and then put in for all of the PTO I have with Centene, to be taken ASAP. I'd time it so that the Centene PTO time off would run out just before my start date with the new job. On the last "work hour" of my last day of PTO, I'd notify Centene in writing that I'm resigning, "effective immediately." This way, I wouldn't have to ever go back into any Centene office, I'd be paid up 'til my last day of PTO, and could just deal with any correspondence with them (always in writing) from home to tie off loose ends.
I wouldn't take part in any exit interviews, or give any reasons why I'm leaving, I wouldn't tell them if I'd gotten another job somewhere else or with which company it is. I'd just give a generic, vague response of, "I'm moving on", and would politely insist that I'm not interested in discussing it further, and would only be communicating with HR and IT at Centene from then on. I'd gray-rock any phony co-workers or my boss, should they pry for details or reasons why I'm leaving. I'd just professionally wrap things up with HR for paperwork, and IT for returning equipment, and leave all of the rest of it in the dust.
Then I'd be starting fresh at a new job, with a new company, for a new year of brightness and light!