This is mostly about saying no to yourself, not to others.
The most difficult part of dedicating all your efforts to one objective is to accept that you are giving up on all the other things you might achieve.
Worse, you need to accept that most people that did that and pursued one single thing were not successful and they simply sacrificed everything else.
The few that succeeded are the ones we know about. We think they chose the right strategy in life, while the truth is that they took the wrong strategy and were very simply lucky.
Taking advice from those people is lime taking advice from wingsuit flyers: not something that smart people should do.
I find I give up my social life to work long hours as a people pleaser. Also I end up doing the low visibility low reward tasks that no one else wants. Just to be a team player. Then appear as a low performer compared to the guy that refuses to do anything that doesn't praise.
If he/she doesn't help you, the best thing is to switch teams (start talking with other people who you helped outside your own team). If that's not possible, start interviewing with other companies without mentioning it to your current colleagues.
I have a friend who was doing the same thing as you, went to another team inside the same company, and actually the same kind of thinking that you have (helping other people) helped him get multiple promotions, and he's a team leader with a nice salary, and his team loves him.
Also one more thing: he was using an old language, that's why he was afraid of switching teams. I suggested him to learn any modern language used inside his company to have leverage to be able to switch company if he wants...he just needed to get a bit outside his comfort zone, after that everything came for him (he's still with the same company, but he's happy now).
