Is the Sovereign class Starfleet's battleship?

Is the Sovereign class the Federation's new battleship equivalent?

Not quite; it is a post-Wolf 359 assault cruiser with greater combat emphasis, but it still retains diplomatic and noncombat functions.

The Sovereign class reacts to Starfleet's losses at Wolf 359 with a stronger military emphasis. It still carries diplomatic and broader mission capacity, which makes battleship an uneasy classification. The design shift also coincides with Starfleet's gradual abandonment of putting whole families aboard frontline ships. Assault cruiser captures a war-focused evolution while retaining those noncombat functions.