Parents, like bosses, respond better to requests for specific things (I want more screen time, or I want to cut back on ski-ing) than to general things (I want more freedom.) So it's fine that you're seeing the connection between these desires, but when it comes time to arrange them, it's better to stay specific. And in fact, there's a big difference between "I want to stay up and play games or talk to people" and "ski-ing is not as important to me as it is to you." For one thing, the first is far more easily reversed if it doesn't turn out well.
At work, one way to get promoted is to start doing the new job. I don't mean start staying up late, though. Right now, do you have to be pried out of bed in the mornings? Are your parents putting in a lot of work waking you, prodding you to shower, dress, eat, asking you if you have all your school stuff? If so, work on that end of the deal first. Ask for an alarm clock if you don't have one. Wake up and get through your morning routine on your own initiative. Surprise them. If you spot an opportunity to do something extra, like tidying your room or getting ahead on some other regular chore, do it.
If your parents are controlling your bedtime because waking you is a lot of work, this may get them to stop. Or, if they are controlling your bedtime because they see you as still a little child, this may change their view of you. Of course, it may have no effect, but these are skills you need to develop to be an adult in this world, so you might as well develop and demonstrate them.
The ski-ing is more complicated. Are you trying to make a particular level or team? Are you working towards a particular goal that requires such a level of commitment? Is that a goal you want to reach? Or is this something they chose for you that you would rather just do recreationally? Olympians typically sacrifice their social lives for their sport, but that doesn't mean you need to. That said, if you don't want to ski so much, you don't arrange that by saying, one Tuesday half an hour before you're supposed to leave for the hill, "I'd like to skip practice today." Instead you need to chat with your parents over dinner or in the evening (when you're all caught up on everything including homework and chores) about the role of this sport in your life. You need to know, before you start this conversation, if you want to quit the sport entirely, or drop down to recreation, or just skip the occasional practice a few times a month. You also need to know if it's possible to stay at this level with the occasional skip (a chat with your coach or with fellow skiers, especially those who don't ski every day, might be good research) by making it up in the morning, or going longer some days, or doing weight training at lunchtime. When you talk to your parents about this, make sure you focus on what you want to do (go out in the evenings with your friends once or twice a month) not what you don't want to do (ski every day.) If they say "but you'll never make nationals if you skip a day" you can either reply "I don't want to make nationals" or "Coach Judy says once or twice a month would be ok, especially since I'm doing weights three times a week now in the middle of the day." (You cannot possibly be the first 14 year old who felt the pressure of a social life against a ski-every-day practice routine.)
And resist the urge to tie it all together into how they control everything you do including when you get up, when you sleep, what you eat, and what sports you do. That might sound like an important complaint to raise. But imagine a two year old saying that. The parents would laugh. "Of course we do! You're a toddler!" Sure, you're not a toddler any more. But it takes time for parents to notice that, and they may consider a 14 year old still a very young child. They will start to let you make more choices over the next few years - each family has their own pace for this - but it will be because you've shown you can make and execute good choices, not because you have stomped your feet and demanded your almost-adult rights.