Contact the artist and agree to an individual contract. Buying an NFT is not legally clear as to what kind pf rights are actually being sold.

Especially if I intend to use that art for a commercial activity, just buying the NFT is an incredible risk.

Unless the NFT itself includes a legally binding contract, that specifices the exact details of the deal and unless the buing of an NFT is legally recognized as actually agreeing by all parties to the contract in it, you are just buying bragging rights.