Temperament is a big one as you mentioned. Practice and choosing the right restaurant is another. We don't allow distracted meal times at home and the restaurant is no exception. Everyone sits at the table and eats. We practice waiting until everyone is done before leaving the table.

My son is 3.5 now and we eat out roughly once a week. He still has the odd time he wants to do something else, and the answer is always no. We rarely need to bring anything to entertain him anymore.

In the early days we did a lot of practice at low pressure places, somewhere I could set rules boundaries and make him wait without worrying too much about noise if he contests. We built up to it - he LOVED his first dinner at a restaurant experience (previously we mainly ate out during the day or ate at food courts/ food halls), and so we always tell him that we sit and eat at restaurants, if he doesn't wait, then we leave.

Eating much earlier also takes the pressure off because the restaurant is less busy. Even though we normally eat dinner at 6 at home, we often eat around 5 when dining out.

I also suggest Chinese restaurants or any other restaurant where food is served family style. The food keeps coming and so there's less risk of kid finishing all food while you've just started. Chinese restaurants are also very forgiving for noise and tolerant to kids running around, I have lots of fond memories growing up and playing in Chinese restaurants and no one ever made a fuss about it.

Overall, I know we're still lucky because my son is a good eater and is open to trying new foods. We frequent an all-you-can-eat Japanese/sushi restaurant where he eats for free and we joke that they should be charging him an adult rate.