Here's what is happening:
Multiple modded clients will soon support having an increased totalScore limit.
The next released version of Digital Client, oldsu! flandremod 1.6, and a future version of modern b1816 will increase the score cap from 2,147,483,647 to 4,294,967,295. This is enough that this map can get ranked, however it's not without some concerns.
Issue 1: If you are using a client that has the original score cap, and your score under flows, your score will not submit. You can still use these clients to submit scores that are under the score cap (such as using NF, or by just missing).
Issue 2: If any score on the leaderboard is above the original score cap, clients without the increased score cap will fail to load the leaderboard. Not much we can do here, those clients are expecting an int not a uint.
So basically what I'm saying is, this map can be ranked, but not every client will be able to play this map as intended. Originally we didn't want to rank this if the only client that could play the map was Digital Client. The last thing we want is only 1 way to experience a map on Titanic, as that goes against the spirit of Titanic in general. With Modern b1816 existing that means that users will have at least two clients that can fully support this map!