How to make fixture of this part for machining in 3Axis machines vmc

Machine a circular nest that locates the OD and supports the taper. Clamp from the top with a ring or straps to prevent distortion.

Zero once and use the 4th axis to index each hole. If seating feels unstable, add a center plug or soft jaws bored to the profile for better repeatability.

I haven't completed this yet; some work is still left. In my opinion, this would be the best choice for doing it in 3-axis milling?
Now we'll have to do it one by one

Since the part is already turned and has a center bore, the best solution is to use a mandrel fixture.

Method:

Machine a mandrel with a precise diameter matching the center bore.

Mount the mandrel vertically on a base plate.

Slide the part onto the mandrel to ensure concentric alignment.

Use a top clamp plate or nut to secure the part.

Fix the base plate to the VMC table.

This ensures:

perfect concentricity

rigid clamping

accurate PCD hole machining

Alternative method:
Use a custom pocket fixture machined to match the bottom profile of the part.

Mandrel fixture is the most accurate and commonly used method for circular parts.

Fixture to do two holes in operation. Using the vise you will have the option to have two fixtures. One operating in the machine, the other reposition parts.