The Iluka Executive Tote was built around this exact problem.
The insulated compartment sits at the base of the bag. It is separate from the main cavity, fully sealed with its own zip, and lined with a wipe-clean thermal interior. It holds a standard 750ml container and a water bottle upright without warping the sides of the bag. The structure of the compartment means the bag holds its shape whether the compartment is full or empty.
Around it: a 16 inch padded laptop sleeve, hidden card slots, a key leash, a charging port that connects to a power bank in its own pocket, convertible straps, and a rear luggage sleeve for travel. The material is eco-luxe vegan pebble leather in Mulberry, Driftwood, and Charcoal.
The bag does not look like a lunch bag, or a laptop bag, or a work tote that happens to have insulation. It looks like a considered piece, because it is one.
For keeping the rest of the bag's interior precisely organised, The Marli Essentials Pouch sits inside the Iluka as a tri-fold system and gives everything smaller a permanent home.