Do you all use dry box to keep the camera and lens ? If yes, which model or brand do you recommend ?
No. It obviously depends on where you’re travelling and what you’re doing with your camera, but I just use a regular camera bag and make sure it stays dry. The one time I had water damage was when the camera was in use and I was actively taking pictures, so the best case in the world wouldn’t have helped me there.
Is insurance a good idea in case of damage, theft, loss, etc ? If yes, which plan or insurer to consider ?
Insurance is a bad deal for the person getting the insurance (=you), at least on average. The insurance company has a lot of CEOs, workers, buildings, vehicles, lobbying and advertising to pay for and these things are paid by the difference between what you pay them and what they pay out in case of a claim.
So you don’t get insurance to save money. If that worked, insurance companies would all go bankrupt. You get insurance for things that would have a disastrous effect on your life if they happen to you. For example, you get health insurance so in case you get sick, you can afford treatment. Or you can insure your house if you would be homeless in case it burns down.
If photography is just a hobby and maybe you could even afford to buy a new camera in case the old one was stolen/lost/broken, then you really shouldn’t insure it. I would only consider an insurance if it was my job, I depended on the equipment and I didn’t have the funds to buy it new.