Wynn Resorts, Limited (NasdaqGS:WYNN) is looking to unload its online sports-betting business at a steep discount as the fledgling niche faces painful losses from stiff taxes and costly promotions needed to lure customers, The Post has learned. The Las Vegas-based casino giant is quietly shopping its Wynn Interactive unit — operator of the WynnBet online gaming app — and has slashed the asking price to $500 million after floating a $3 billion valuation less than a year ago, a source close to the situation told The Post.