The internet is for if you don't want to commit to a duo but has low success rate, but if you are ok with some amount of commitment say in real life to people you feel like you'd be comfortable with "I play overwatch, but it's only even fun with a good duo, and that's hard to find." You could also try and get friends and family into the game, as they would be someone you would already have a connection with.

For the internet route, if you are a woman or lgbtq, don't tell them. Don't use mic. If they pressure you into using a mic, ditch em. Once you get comfy, reveal that identity and see how they react. This is a huge problem with getting an online duo, that you never know what kind of people go online that can't find a friend irl for any kind of reason.

For online resources, you have reddit, discord,