Is a bq2920x enough to protect a two-cell Li-Ion battery?
The bq2920x IC is a smart battery fuel gauge chip useful for longevity of the battery but does not offer any safety features, per se.  The Typical App does show some protection for current flow direction with a dual FET which can be purchased.

PACK +/- are on the same voltage Nodes as Cell2+ and Cell1-  ( i.e. direct connection. )