Is there anyway to add BTC into metamask or its impossible? Also other wallets have BTC and alts in them like trust and atomic wallet but why not on metamask?
Well it is impossible --why?
Metamask wallet is an Ethereum network wallet while bitcoin has its own network and is based on a blockchain network.
Separate your bitcoin from your altcoin, you can use both Electrum for bitcoin and Metamask for your altcoin, they are good wallets the same open-source wallets. But if you can afford --a hardware wallet like Trezor or Ledger would be the best, it supports most coins including bitcoin and altcoins.