I see that TrustWallet is also a good and popular wallet in the crypto arena, both wallets are good for beginners and many tokens are available on them, and any user can manually add the network he wants for any token on both wallets. As for me, I have been using them for many years and have never had any problems with them.
As mentioned above MetaMask only supports ETH-like crypto, so you can't store coins like XMR, XRP, BTC, and so on there. They also collect some personal info like IP address when you connect on their default RPC. While you can switch the RPC to another one, most of the time you need to register on another service (some are free, some are paid).
If privacy is an issue, what can OP do is run a bunch of open-source wallets for different altcoins and use Electrum to manage his BTC. As long as OP manages his backup properly, it should be fine. Relying on a single app with unverifiable code is definitely not a good choice to store most of your crypto. CMIIW.