We have 2x4 studs with drywall and 1"-1.5" of exterior insulation and vinyl siding on outside bringing the total wall thickness to about 6".

Marvin Elevate French Sliders (wood/fiberglass) has 2 jamb sizes 4 9/16 and 6 9/16. The latter is too wide and the former needs an extension jamb.

Supplier suggested extension jamb on the interior as this looks better but everyone always say don't fuss with extension jambs, get a jamb that covers your whole thickness.

He said I could do custom jamb size but sounds like the piece arrives separate from the door. I'm not sure if this has any bearing on longevity.
Here is a video on my wall condition: https://www.dropbox.com/s/cn7olfo8xqo1h9s/20221006_081122.mp4?dl=0

What should I do? Go with suggestion of 4 9/16 and add extension jamb on interior side? This is a 15 week lead time wait and don't want to mess order up, thanks for any guidance!!