Victoria 3 is a long-awaited game. As such, everything must be as close to perfect as it is possible, to ensure the game doesn't suffer from the same fate that Imperator did.
For those that are unaware, there's a cheeky way you can tell what date developers set a steam game to release when it says "To Be Announced."
On the steam upcoming releases page, you can search all upcoming releases and scroll for ages until you come to the game in question, as this page is ordered by internal release date set somewhere in steams back end. Neighboring games with an absolute release date set will give us an idea of when the game in question is to release, and Victoria 3 is in between a game set for February 1st and February 2nd of 2022.
This was a few months ago, and it seems that this was a placeholder, as the game's hidden date is now moved to late 2022.
Though a 9-month announcement to release window is well within the norm for Paradox; Stellaris had a 10-month gap, CK3 an 11-month gap, while Hearts of Iron had the longest one due to delays, Victoria 3 is unlikely to follow the established rules.
Victoria 3 is a game that is set to be Paradox's revival, after the flop of Imperator. This means that the game must leave an incredible first impression, and to do that, developers need time and community feedback to implement it into the game. It is unlikely, therefore, that the game will be released after 40 developer diaries or so.