Again with the anecdotes.
I would suggest that your “friends” who are having problems should quit, much like I would suggest an alcoholic should give up the booze or a heroin addict should get off the smack.
There are numerous studies that prove that cannabis is much healthier than alcohol, opioids, coke and many other of similar ilk, but like everything , it’s not for everyone and when it becomes a problem it should be stopped.
And although there are some studies that it “change your brain slowly”, it’s universally accepted that this is long term, very heavy usage and to infer this is what will happen for the majority is just scaremongering nonsense.