Hitscan hero pool

I know common advice is to learn 2-3 heroes very well to grow. I'm just curious for the hitscan role since playstylea are so similar is this advice valid?

I typically otp S76. But I am doing my best to branch out. So far I also like emre a lot, and getting more familiar with cass. But my concern is that soldier and emre play so similarly that I am not covering my bases. I know sojourn is popular but I'm pretty bad with her. Are there hidden rules or understandings to building a hero pool for hitscan? I don't quite understand how to play the role "properly" since I just go into the game and kill the enemies best I can. But I'm trying to make smarter decisions so I can climb a bit easier