Also, re: "Don't stop until you've signed a new hire offer elsewhere."
Once your new hire offer is signed, and your start date with the new company is finalized, block off all the Fidelity vacation time you've accrued that you're able to take, directly before your start date at the new place. If your current creep manager needs a reason for why you're taking time off, tell them that it's regarding arrangements for moving. Again, this isn't a lie, because you are moving, just not where they think you're going!
Enjoy your time off before starting at your new job. Bask in the sun, day-drink, whatever best helps you to unwind. Ignore any and all pings/emails/texts/calls/calendar invites, etc. from anyone at Fidelity (especially your manager) during this time off...really decompress. On the last day of your "vacation" time, get into your work stuff online and save anything personal you want to keep, and delete anything you don't want remaining. Don't forget to d-load personal timesheets, your financial/tax info., & contacts: both external and internal (especially those for various internal IT and HR teams/individuals). Double check that you've gotten everything, because as soon as you do what's next on the list here, your access might be cut off.
Now you're ready for the biggie: Email your manager, while cc-ing your manager's boss and HR, letting them know that you are resigning, effective immediately.
You don't have to give a reason, you don't have to give 2 weeks' notice, you don't have train any replacement or transfer any files, you don't have to fill out an "exit survey" or take part in an "exit interview." Just say that you're finished with working at Fidelity, and prefer to not discuss it any further. Cut'em all off, clean. You then never have to step foot into any Fidelity office, ever again. From then on, refer any of your manager's subsequent inquires to HR and otherwise ignore them entirely. Their drama and sadistic game-playing is not for you to deal with anymore. You've liberated yourself. Only communicate electronically with HR at this point re: wrapping things up, returning badge/laptop, e-signing any other required offboarding paperwork, arranging for last pay, and that's it! You're FREE!
(And you d!cked-over your d!ick manager, in the process.)
Let them squirm to figure out at the last minute how they're going to fill your position/re-assign your work, etc. LOL
Enjoy life!