The usual is to get out of town for a month or 2
If you don't want to uproot, when you come back private up your social media, change your phone numbers and move locally to another location and give the people you still want in your life your new contact information.
Then prepare to do it in a few months one more time as you find people who thought were your friends either arn't or are easily swayed by money.
It's amazing the stories I've seen.
Sometimes they are out in front.
Often though it's a slow process. You start shelling a bit of cash and they start to develop expectations, that grow and grow until you become their cash bitch. Hey lets go to that fancy place, buddy will pay for it becomes hey lets go to this resort, buddy will pay for it to hey lets set up an all porn start orgy, buddy will pay for it and the moment you draw the line, many will turn on you for being cheap [yeah Irony, many are not quick to pick up on it]
Seems a lot of people will do this
Then you get the, How come I got a Corvette like buddy, I'm your best friend, i should get a lambo. Or how come I got a Camry when the other guy [a child hood best friend] got a Lexus ES350. You can' win.
If you win the lotto and want to retain family and friends from your past life, best thing to do is sit everyone down and tell them nobody gets nothing because this sort of stuff creates too many problems, changes the dynamics of relationships and is just a bad idea. Those who bitch, well fuck them
Hell I've known acquaintances who have asked me to buy them a car when I haven't even won yet. Not friends, but someone who basically calls me only when she needs a ride [but down pay for gas, wear and tear and a bit for my time because I ain't no simp]. The nerve.
I've had other people do the same and I think... yeah, having you in my life is fine, but you are not that important to me, but I don't say it. People I see very infrequently.
My actual buds, they all know if I win the lotto, they ain't getting shit. My maternal unit is dead, my paternal unit is extremely old and won't live long enough to spend the money he has, can't travel etc, maybe a Lincoln Town Car for him if he is still around. My sibling is a bit of an ahole who always makes fun of me for playing the lotto, and he is pretty well off and near retirement. Cousins, I haven't seen many of them for over 20 years and would probably walk past most of them not knowing who they are. Aunts and Uncles, dead or french and well off and I don't speak the french.
But seriously though, nobody gets anything unless they are immediate family and even then on a case by case basis. Make it s strict rule, don't be the guy who pays for outings, just cover your fair share. It will solve and prevent so many issues. Don't be a cash cow, don't be a pay pig, don't be the money bitch.