I’m trying to use Google Takeout Transfer and it’s taking a really long time, failing, or not moving all of my content.

Unfortunately, if you are moving more than a small amount of data, it has a higher chance of failure. Since Google doesn't directly support Takeout Transfer, we recommend using VaultMe instead. It is guaranteed to work and has a dedicated support team. You can learn more about VaultMe here - https://www.vaultme.com/edu/ucberkeley