You could build any character you’d like. There’s no “right” technique to make a character, particularly in 5e. No matter what you select to do the character will “work”, but in case you’d like some ideas for using a goliath’s stats much more optimally the next builds are good starting https://firbolgcleric92368.get-blogging.com/28475869/the-greatest-guide-to-tiefling-warlock-build