Help! My burgers suck!

Even the dogs won't eat them so certainly my darling little demon spawn won't either!

They say they lack flavor, texture and taste but I don't understand because they used to clean their plates right into the trashcan.

I get the finest meat that dollar general has to offer (expired but 10lbs get 5 free!) and mash it into a pulp with my shoe. I throw it on the grill and even use fancy brioche buns! How could they not like them??

I've never seasoned anything before but they say the burgers are bland and boring. I don't own salt because sodium is unhealthy. I always just assumed the grill seasons the burgers and I dropped them on the floor so that also imparts some flavor, right?

I eat mine raw so it's probably because they want theirs actually cooked with char on them.

Does anyone have any advice??