Yes, Ideanote supports RBAC. Ideanote has three access systems, rank-based, team-based and sharing-based.
Rank based: Ideanote users can have the Workspace Owner, Admin, Team Owner, Member, Guest or Visitor rank. People logging in via SSO automatically become Members via Just-in-Time provisioning (JIT). You can choose to give some people a higher rank. Admins have editing rights for all content they see, including editing and deletion.
By default, idea collections (the default content in Ideanote) are not shared with anyone - access can be given in a fine-grained manner and include access levels like content visibility, contributing ideas and comments, evaluating ideas and more.
To make RBAC easier, users can be grouped into teams and teams can be given access collectively, e.g. to add ideas or comment in an idea collection.