Is it permissible to work in a restaurant that serves pork and other foods, knowing that the nature of the work involves preparing sandwiches and wearing gloves?

It is not permissible to sell meals that include forbidden ingredients, nor is it permissible to assist in their preparation, due to the generality of Allah's statement: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." If you are unable to limit yourself to preparing permissible meals, then you must leave your job at that restaurant. It is not permissible to remain there except for what is absolutely necessary, while also being obligated to dispose of a portion of your salary corresponding to the forbidden work, and to seek a permissible source of income. If you can limit yourself to preparing only permissible foods, then there is no sin upon you, although it is better to leave it entirely. Whoever abandons something for the sake of Allah, Allah will compensate him with something better. And Allah has promised the righteous a good provision.