If there was only the ETH withdrawal and the deposit of 5 NFTs, you could simply merge the 5 transactions and Koinly would give the correct cost basis to the NFTs received.
How to merge/split transactions manually
In this case, though, you should calculate and add the worth of the WETH and the NFT spent and divide it by 5 to have the cost of each NFT. Then edit each NFT you received and change the worth of the NFTs to have the correct cost basis.