I recently came across this problem (and felt slightly desperate 😅), but I managed to solve it as follows:
1 - I accessed the 'privileges' page of the Workflow documentation (https://enterprise.arcgis.com/en/workflow/latest/administer/users-groups-roles-and-privileges.htm#ES...)
2 - I copied all the values from the 'Privilege' column to an Excel spreadsheet:
a) I surrounded each of them with double quotes ( "" );
b) I concatenated them all into a single cell, separating them with a comma ( , )
c) I enclosed the final result in square brackets ( [] ).
The result is this:
["adminAdvanced","adminBasic","jobAssignAny","jobAssignGroup","jobAssignIndividual","jobClose","jobCreate","jobDelete","jobForceStop","jobReopenClosed","jobUpdateAttachments","jobUpdateDate","jobUpdateDescription","jobUpdateExtendedProperties","jobUpdateHolds","jobUpdateName","jobUpdateNotes","jobUpdateOwner","jobUpdateParentJob","jobUpdatePriority","jobUpdateStatus","jobUpdateVersions","jobUpgrade","viewCreatePanel","viewDetailsPanelAttachments","viewDetailsPanelComments","viewDetailsPanelDiagram","viewDetailsPanelHistory","viewDetailsPanelHolds","viewDetailsPanelLocation","viewDetailsPanelNotes","viewDetailsPanelProperties","viewManagePage","viewWorkPage","workflowSetStepCurrent"]
3 - I accessed the hosted layer generated by WorkFlow and accessed the 'roles' table
4 - I copied the value from step 2 in the 'workflowPrivileges' column of all rows in the table ('roles')
This way, I regained access to all WorkFlow functionalities and was able to redo the access configuration.
I hope it helped you.