If you remove a question from a Survey Template that is used on multiple projects, the question will be removed from the Survey Campaigns on all of those projects
It is not advised to edit a survey that has already been distributed or analysed. It would be better to duplicate the original survey and edit the new one. If you would prefer to copy a survey template, follow these steps: Copy a Survey Template
Steps
Press the Delete Question button that appears next to each question in the Your Questions section on the right
Scroll to the bottom and press Save