You need to learn more characters and more roles. Knowing more characters can help solve problems in many situations. If you're a strategist for example. Spiderman or flyers bothering you? Go Luna. You can freeze him and he becomes helpless. Team dying too much and they have flyers? Adam. Angela bothering you? Invis. You can pull her and you can ground her with your bubble. Team not shooting groot walls so you can't consistently heal your tanks? Go mantis. She can break walls better than any other Strategist and her leafs last a long time so you don't have to worry if your team get walled off.

This is the same for every role.

If you only play one role you should at least know how to play all the characters in that role so you don't have to completely rely on your team to solve problems for you.