Metamask is merely an application in the form of a browser extension. It is not an integration point. The respective blockchain is.

As Petur said, you just need to add the blockchain/networks/"mainnets" with the associated address.

Individual application integration is pointless, especially given that you can use the same mnemonic/passphrase with multiple applications at once (not a good idea, but can be done). And should those applications use the same derivation path, you will see the same address, transactions, and balance.

The mobile/desktop application you use is merely an interface/GUI for interacting with the blockchain, it doesn't contain your crypto. Your crypto is never actually "in your pocket", only your keys and access to your crypto is. Really, no different than the currency in your traditional bank account is not in your pocket, despite you having a debit/credit card and/or mobile app with access to it, the currency is still sitting at the bank (really, its just on the banks computers, they don't actually have every account holders balance in physical currency at the individual branches).

The "wallet" in the names of these mobile/desktop applications is a misnomer. They really should be called interface apps.

The Metamask wallet on Koinly will only sync data from the ETH blockchain but we support a lot of other blockchains as well.

To add a different blockchain, just click on 'Add Wallet' and go to the blockchain section to see all of the options.

Some of the Metamask-compatible blockchains that we support:

Binance Smart Chain

Polygon

Fantom

Avalanche

Cronos

Arbitrum

and more (check inside the Koinly app for an up-do-date list as we are always adding new integrations)

Yes this should be top priority

Yes, please add others! My first vote would be for the Polygon Mainnet.