Okay long txt..
Luck is the belief that random events are influenced by outside powers other than actual scientific probability of occurrence.
For example a person who flipped a coin and got heads 3 times in a row would attribute this to luck instead of standard deviation of the probability to produce a 50/50 result.
Risk is the determines chance failure before the stated chance of success is realized, or the percentage change of success based on measured outcomes or a given trial.
Can in an English sentence normally denotes a wish or statement that the proposition referred to by the statement is true, positive or intended.
I can double down if I want to.
We know that you can.
Could in an English sentence normally denotes the possibility of the action or wish, but infers dubious intent or success of the stated subject of action.
Well you could double down on 2,2
Well we know you could.