I usually regret the classes I’ve boosted… 27 rogue vs a 120 rogue is day and night. Same goes for other classes and specs…
Go do a trial character, and just level something to 120 that you think you enjoy most.
Most are viable anyways unless you do serious Mythic raiding or high M+ keys were it becomes more choosy on behalf of the lead to whom they want to make up their comps.