Hello! It's great to hear that your partner has decided to enter the world of Bitcoin. Coinbase is indeed one of the most popular platforms to buy bitcoin, but as you mentioned, there are limitations with this platform.
If you're looking for alternative options, I recommend trying out decentralized exchanges such as Bisq. While these exchanges may not have the same level of liquidity and ease of use as Coinbase or other centralized exchanges, they do offer a level of privacy and security that is unmatched.
Another option to consider is using peer-to-peer marketplaces such as LocalBitcoins or Paxful. These platforms allow buyers and sellers to transact directly with one another, ensuring that your partner can buy bitcoin quickly and securely without the need to wait for lengthy lockup periods.
Regardless of where you choose to buy bitcoin, it is important to remember to always practice good security habits when handling your cryptocurrency. This includes using strong passwords, enabling two-factor authentication, and keeping your private keys secure.