Amazon have clarified the new rules regarding character names after deletion and when they are released. If a characters never attained level 11 (or rather level 1 as that's the first one you get, since you start at 10) their name is released immediately upon deletion. Otherwise it will take 60 days for the name to get released.
Name Deletion (Source)
Greetings, heroes! We have an update to share on what happens to character names after a character is deleted.
When a character that is Level 10 or lower is deleted, that character’s name will be available for reuse right away. If a character is Level or 11 or higher, when they are deleted their name will be recycled for reuse after a 60 day period passes.
We hope this makes things a bit easier when it comes to naming your character in Arkesia!
Source: News Latest Topics https://www.icy-veins.com/forums/topic/64175-lost-ark-name-deletion-clarification-and-update/