Hi,
Welcome to the forum.
Four-letter (non-word) dot coms do not have inherent value, unlike three-letter dot coms, which definitely have inherent value.
Even the worst letter combinations with three-letter dot coms will be worth at least high $xxx. And good letter combinations will be well into the $x,xxx range.
Four letter dot-coms can be valuable if a company wants the letter combination as an acronym, and if that is the case you could possibly get low $x, xxx for the domain.
Unfortunately, not many four-letter dot coms sell for that.
If no end user is eager to buy the domain as an acronym, the end user value is relatively low: $xx to low $xxx range.
Good luck