>

With some know how, it's not out of question to get the open source schema and modify it yourself to fit an encoder. Coseyfannitutti did a great putting his design out there for us to tinker with.
Is this a Disc65 with rotary encoder? >

Looks like it >

But where. Need. >

You can’t preorder the Discipline V2 anymore unless you buy it second hand >

V2 doesn't have an encoder afaik. Just ISO which I don't give two shits about.
Curious where the Encoder variant is.