Hello, what should we buy for license type to create Win11 pooled Desktop VDI in Citrix CVAD ? Should we use KMS server to activate the VDA Win11 license provided with MCS ? Thanks

KMS is preferred for non-persistent.

Why not using ADBA? As targets are domain joined this is way smoother than a dedicated KMS host

Can I use ADBA on a specified OU to only targer my Wiçndows 11 VDA and not all the physical Win11 computers that are existing in AD ?

nope, with ADBA you can only activate the entire domain. Then you need to use classic KMS Disable DNS publishing on the KMS host and activate your targets with /skms command (startup script)