It really depends on what type of game the gambling is taking place on(dice, crash. ect)
if its one played against the house and not other players i think its both luck and strategy in a sense.
Ultimately it is more or less 100% luck but you can employ different strategies to have a bit more control over the luck. more often than not that will work for short term sessions but luck being luck if you push it to far in one go without changing things up you will most likely rip as the variance comes to bite you
It`s both, only thing that depends is will you make money or not. You will play some strategy and you will win, next time with same strategy you will lose, sometimes you need to just be lucky, what ever strategy you use.
In gambling not even one strategy works all the time. I always say that you need to mix you strategies, your gameplay, with simple words try to be unpredictable and that`s something that you can apply on every gambling game, live and skill game or lucky based game.
Oh absolutely, sticking to the same strategy over and over without changing anything will come back to bite you due to variance.
also learning when to stop and run helps a lot, if you more than triple what you started within a short amount of time maybe you should call it for the day before losing everything you just made.