Drawing the creator-income versus flipper-CGT line
HMRC draws the line using the badges of trade. Creating NFTs and selling them, especially as an ongoing activity with a commercial purpose, is likely to be trading or professional income taxed at your marginal rate. Buying existing NFTs and reselling them is usually CGT. There is no bright-line frequency threshold; the classification is a facts-and-badges judgment, and borderline cases need a documented opinion, not a guess.