You need to license all hosts the VMs can run on.
A license covers 16 cores.
A standard license covers 2 VMs.
10 VMs on a 16 core server = 5 Standard licenses. Multiply by 2 because you have 2 servers. So 10 standard licenses.
CALs cover all servers up to the level of the CAL. Doesn't matter if you have 1 or 100 servers.
The breakeaven point between Standard and Datacenter is 13 VMs. If you are doing 13 or more on a host, it's cheaper to buy a Datacenter license for the host which gives you unlimited VMs on that host. You must license all cores as usual. If you had 13 VMs I would have suggested buying 2 Datacenter licenses (1 for each host).
I have 1 ESXi host (128GB RAM with Intel Xeon 16 core CPU, VMware Essentials Plus) that runs 10 Svr 2019 VMs (Purchased 5x 8 qty "2 core packs" from MSVL, aka 5 svr 2022 std licenses with 200 server 2022 CALs). I have 172 users.
For redundancy, I added another identical server to the VCSA and enabled vMotion in Mar 2022.
Now....How many Svr 2022 std licenses CALs do I need ?