UbonLarge Duffel Bag Weekender Bags with Shoe Compartments 4-Way Sports Gym Backpack with Padded Straps Camping Traveling Duffle Bag

Will this pack flat enough to fit into a suitcase? I need a duffel that's rugged enough to check but flexible enough to fit in another bag

Has anyone used this bag for scuba gear? say the large 60l probably? is it big and strong enough? thanks

What are the biggest size shoes that will fit in the shoe compartment?

What is the longest item I could fit in the main compartment (since I assume side pockets take up some of the length dimension.)?