Is being a hotel cook stressful? ?

Almost any job is stressful t times.  Hotel cook is not a generally high stress job.

That depends on what kind of cook you are.  If you are a prep cook, that would enable you to avoid the stress associated with  restaurant kitchens because you would work before the meals are served.  As for the stress involved doing a job you are untrained to do, that is going to happen anywhere.

If working during meal service, yes, it is a very stressful environment because everyone is in a rush.

You will experience a lot of stress trying to learn the menu and how to prepare the items on the menu to the standards of the chef you work with. Maybe ask  for a prep cook job to learn a bit more slowly.