A gas fee is a fee that miners pay to use a blockchain to get a user transaction in it. Gas fees are not fixed, but they are an important aspect of minting NFTs. Some miners pick up transactions that pay more, not just the ones that only pay less.
It makes them pay to get their transactions included first, fast, and effectively. EWallets such as Metamask allow you to choose what gas to pay and contact them. The gas fee on Ethereum is so high.
The chain has a large market cap, a large volume, and transaction fees jump as demand increases. You can monitor gas prices on many websites such as ethgastation.com or Ethereum price. A variety of protocols are challenging Ethereum as the base layer 1 for web 3.0 projects.
Gas prices are lower because there is not as much traffic in blockchains. There are less of dApps operating on them at least when they are. Crypto markets are in green for the second day in a row.