Hi there. May I confirm the swap you mentioned from BNB to ETH happened on the BSC network? If so, then the ETH is a Binanced pegged ETH. You can refer to this thread here as well. ETH from Binance to MetaMask
If you need further assistance on this, please open a support ticket here with necessary info https://metamask.zendesk.com/hc/en-us
Be aware of scammers and not share your seed phrase-secret recovery phrase.