What would be your advice for such if they were to be your friends as a caring friend who want them to not get financially drained in the process?
My concern is how do they get these extra funds that they use in staking since they are staking with an amount that is above their salary. It shows that they're gambling for profits and at the same time chasing their losses. My advice to such people is that they should go on a break from gambling and focus more on their work before they get addicted.
They may have different loans since they can't maintain such activities when they are betting more than they can earn. I also think that these people are in a profit since @OP is very concerned about his friends.
I hope @OP can find a way to divert the attention of his friends from time to time to at least have a break on their gambling activities. In addition, @OP can have a heart-to-heart talk with his friends, if he is very close to them and has them open up to him about their struggles in their gambling activities. I think it is the only way to give solid advice without offending the other parties.