No, it's not sinful to be wealthy, though it would be sinful to hoard wealth or spend the wealth on luxuries when there are people out there in need of the basics.
If I won the lottery or something, I would make sure my children were taken care of (set up in life), make some preps for whatever is coming, and then give the rest away to people who are truly in need. Probably the most I would do is to put away enough to retire on, quit my job, and then dedicate the rest of my life to prayer (including praying for those in need) and other service.