Animal companions and familiars are done ALL wrong in BG3.

1. Familiars don't attack. They are an extension of the mage. A mage casts touch spells through the familiar so THEY don't have to get close.
2. Animals have prof bonus.
3. Animals require action/bonus action to command based on beastmaster special abilities.

The list goes on.

In short, they redid the whole system for animals and familiars.