I have been on a medical accommodation and I'm feeling pressured by my workplace to quit/ go on a leave of absence and self demote to a lower paying position.

Thanks for your questions. You do not need to accept a demotion to a lower paying position. If the employer forces it on you unilaterally it may be the basis for a constructive dismissal.
If they force you to go on a leave of absence this also may be the basis for asserting constructive dismissal and may create the basis for a human right claim.
Do not quit your position without first speaking with an employment law professional, as quitting would likely impact your common law entitlements.
I would recommend consulting a lawyer before making any decisions about the issues you are facing.