If you can use Firefox, it allows you to create multiple "containers", each with its own set of cookies and other state. You can create a separate container for each Okta login, then you can be logged into all three accounts simultaneously.

Also you can create a separate browser profile for each account. This works with all browsers but is less convenient, because it forces you to have a separate browser window for each profile, and also you need to enter all preferences for each profile separately.