Not surprising considering how poorly King of the Monsters did here (made roughly the same as Dark Phoenix and MIB: International in June 2019 yikes) and GvK not getting a proper theatrical release besides somewhat hanging around when cinemas did reopen in May 2021. Trolls Band Together dropped a third on the first one after World Tour went to PVOD, so if we treat this more as the third Kong entry, a little over £10m might be a fair expectation for this.
Anecdotally, I've walked past a couple toy shops in the last few days and their windows are fully kitted out with toys for the film with proper displays and everything. No Kung Fu Panda or Ghostbusters toys either, just Godzilla x Kong. Wondering if WB/Legendary are gearing more towards families with this one, could mean it's more walk-up friendly throughout Easter.