Load Correct Canvas Size Based on WooCommerce Product Variations

I need help configuring a WooCommerce product called "Photo Poster Printing", which includes multiple product variations such as A4, A3, 11x14 poster, etc.

✅ What I want:

When a customer selects a variation (e.g., A4) and clicks the Customize button, it should load a canvas in that exact size (e.g., A4 paper size).
Likewise, selecting A3 should load an A3-sized canvas, and so on.

❌ What I’ve tried (and the problems):

I created one FPD product called Photo Poster Printing.

Under Product Builder > View Options > Print Size, I added views for A4, A3, etc.