Lenovo Legion 5 Pro 16ACH6H Left SSD Replacement - iFixit Repair Guide
How to upgrade the SSD in the Lenovo Legion Go
Yes, Legion 5 Pro has two NVMe PCIe 3.0 2280 SSD slots, the second slot is empty and has a pre-installed heatsink with a thermal pad. (I installed Samsung 970 Evo 1TB
How to upgrade the SSD in your Lenovo Legion Y740 | Windows Central