I am able to resolve this by overriding middleware  django_tenants.middleware.TenantMainMiddleware
I have overridden django_tenants.utils.tenant_context to activate a timezone specific to the tenant.
class NewTenantContext(tenant_context): ...
I can use the new context like this
with ALSTenantContext(tenant): ...
All this works fine for a specific process to start for a tenant.
But how do I make sure NewTenantContext is used when tenant is set from Admin or API?
Django: Multi Tenancy : Override Tenant Context