In cloud computing, multi-tenant shared storage is widely used for efficiency. ZNS SSDs have become a popular choice due to their high throughput and low latency. However, they still face challenges: the zone structure is not exposed to tenants, making performance control difficult, and the multi-namespace design can lead to wasted performance when tenant workloads are highly imbalanced. This paper proposes a tenant pressure-aware performance isolation scheme, called IP-Zone, that partitions users into independent regions and maximizes zone parallelism through cross-resource allocation and flexible address mapping. For severely unbalanced loads, a complementary load-aware strategy dynamically reallocates bandwidth among tenants to improve SSD utilization. Experiments show that this scheme improves IOPS and throughput by 34.6% and 25.0% over traditional channel isolation, while average and tail latencies are reduced by 76.3% and 36.0% compared to black-box sharing.