What to look for in a dog that will maximise the chances it will go well with people, and especially children?

I know there are lots of different opinions out there, and I’m not necessarily looking for ”this breed is your answer to everything”.

I’m wondering what general things I should be looking for when meeting a puppy or older dog. Breed/behaviour/demeanour etc.

Ideal dog would be calm, but not grumpy, and loving of people and children.

(Our current dog is of a breed that should be easygoing and friendly with everyone. He definitely fulfills the ”calm but not grumpy” criteria, however he loves me above all, likes the rest of the family, tolerates friends and is very reserved and slightly suspicious towards strangers. Which is very much his personality, not a breed trait. As a next dog I wouldn’t mind a dog that would happily greet burglers, and am looking for advice on how to pick one lol)