Unfortunately, there is a 1:1 relationship for each of the SSO integrations, so yes, you can have more than 3, but only one of each. Most SSO providers allow SAML integration as well as native SSO, so you could use Azure AD SSO and SAML to a different AD, but not a 3rd. Here an idea that has been accepted, but not in development yet:
https://genesyscloud.ideas.aha.io/ideas/OP-I-555------------------------------
Robert Wakefield-Carl
Avtex Solutions, LLC
Contact Center Innovation Architect
https://www.Avtex.comhttps://RobertWC.Blogspot.com------------------------------