You don't need salt and spices to make a burger, it can be 100% beef with no additives. A pinch of salt can be like 0.3g/burger and you're fine as well.
I don't eat that these days, my burgers are actually 25% beef and 75% lentil/seasoning. Still under 0.5g/100g
Let me assure you that you're in the vast minority if you add little or no salt at all to your home-made burger patties.
I remember working in a restaurant many years ago, where it was part of new hire training to demonstrate the importance of salt and pepper to a burger's taste. We would make 3 burgers, one no seasoning, one poorly seasoned, and one properly seasoned to the spec, and then we would taste test them all. The difference in taste was so night and day I was shocked the first time I participated in the test. Yeah I guess you don't technically need salt and spices, but not adding them or using just a pinch is not the same thing at all.