Hardware Wallets (Ledger,Trezor) are the safest option for storing your Bitcoin, since they hide your keys offline and shield you from hacks.
Set up two-factor authentication , Use strong passwords and avoid sharing your private keys.

Marcus by Goldman Sachs mostly focuses on Savings accounts:

High-Yield Online Saving Accounts: there is no minimum balance requirement and no maintenance fees. You can easily access to your money. It’s good option for short term goals. Good for unlimited withdrawals and provides you facility of same day money transfer.

Certificate of Deposits (CDs): CDs are the safest way to invest money. Their rate is fixed and it gives you guaranteed rate of return. In this you can set aside a particular amount of money for a specific purpose.