Subs are on the way don’t worry they have stated it was underdevelopment. Though Naval is a bit of a schrodinger’s cat of please add one more thing and I will play it bro.
The major issue with subs is one needs to defeat them to prevent people getting nuked by a WW1 sub with zero counter play. Japanese ships might be able to side step them due to them bolting a sonar set to even there battleships.