Where I live, there are no background checks etc. Once you hand in the ticket at Lottery HQ and they verify it's authentic, you get the money.
I'd be one of those anonymous winners who slips away quietly. Our lottery HQ is in a city centre office block. So in order to slip in/out unnoticed, I'd dress in a suit and walk in as an anonymous "office overalls" wearer attending a business meeting in the building. After big wins, press photographers sometimes wait outside looking for the winners, so you need to look anonymous.
I'd tell nobody, except the wife, for several months.
I wouldnt quit my job. I'd wait a few weeks while planning what to do and then apply for a career break for a year or two to travel orvsomething with the intention of resigning before returning - less fuss/attention if you're already long gone and partially forgotten by the time you resign.
Over a few months, I'd gradually dissappear from my neighborhood. Buy a nice, but manageable house in a nice area. Would wait until end of school year to move the kids. Would live a low key lifestyle.
Would keep working in some capacity - maybe for a volunteer organisation, as would get bored doing nothing.