Can I sell NFTs minted on Universe on other platforms?
Yes, for instance, an NFT minted on OpenSea can be sold on Universe and vice versa.
Note— If listed and sold on one platform, you will not be able to sell that NFT again on another platform.
All sales and transfers on the blockchain are final. There are no tools to reverse transactions. You can always use block scanners such as Etherscan to audit or verify successful transactions. Anything that says 'pending' has yet to be confirmed 'on chain'.
If you need to know more about blockchains and transactions click here.