Unfortunately, you will need to re-install. There is no way to re-encrypt the password outside of the installer. See this KB for the steps:
https://kb.omnissa.com/s/article/2960970
Short version, yes.
Longer version:
To use Okta to auth into UEM you would need to configure SAML under Directory Services to use Okta.
If you want to use Okta to auth into the Access portal, you would need to configure Okta as the IDP inside Access and set the appropriate rules in the Default Access Policy to send the auth request over to Okta.
For Mobile SSO to work, Access must be the IDP so you would need to set Access as an IDP inside Okta and then set the appropriate routing rules to send the authentication request over to Access. On the Access side, make sure your Default Access Policy is set so that the rules for Android and iOS are the first ones in the list (for that device type) to be evaluated and set them to use Mobile SSO as the authentication method. I'd suggest adding Device Compliance in there too
Glyn Dobson's post in On-Prem Cloud Connector Stopped was marked as the answer