Hey. It's been awhile since I last played this game and I don't remember my accounts username anymore. I have 4 account's that I used and 1 that I had my gear on and last leveled and I can't remember the username. Everything else I remember password/pin/pic. The account had 14x lv corsair on it named Usoppi.
You may refer to this guide to submit a manual request https://royals.ms/forum/threads/lost-email-or-username.154999/