Insulated bags are sold on a photograph and bought on a price, and neither survives the first hot summer unless somebody wrote the specification down.

What is the foam, and how thick is it?

Closed-cell polyethylene is the insulator, and thickness is the number that matters.

4mm, 6mm and 8mm are different products. A limp panel is a thin panel, every time.

What is the liner made of?

PEVA is the food-safe wipe-clean standard and it softens under repeated hot loads.

A PU-coated liner takes heat far better and costs very little more.

Is the liner welded or stitched?

A stitched liner has needle holes, and a spill goes through them into the foam.

A welded liner is continuous, so the spill stays where you can wipe it out.

How is the outer face going to be printed?

Polypropylene distorts under a normal cure, so large solids wrinkle unless the heat drops.

Sublimation needs polyester. It will not bond to a foil or PP face at any temperature.

And check the fit before you check the foam

A half-empty bag is mostly air. Sizing the bag to the load does more than a millimetre.