This is likely a subscription-level restriction for the Switzerland West (SWW0A) region rather than a normal RP registration issue.
If registering Microsoft.Kusto or enabling feature flags returns Unauthorized, the subscription probably is not allowlisted for Kusto deployments in switzerlandwest.
Please verify:
Microsoft.Kusto RP registration
Required RBAC permissions (Owner/Contributor)
Whether the subscription has Switzerland West access enabled for ADX/Kusto
If not, Microsoft support/service team will need to enable the backend allowlist for the region.