Japanese Nintendo site Nintendo Dream has recently published an informative interview with a number of staff who worked on this year’s entertaining Mario & Luigi: Brothership game for the Nintendo Switch. Mario & Luigi: Brothership co-producer Akira Otani was one of those who was interviewed and he revealed that the team had initially settled on the name Mario & Luigi: Wonder, however, that plan naturally changed when Nintendo revealed that they were working on Super Mario Bros. Wonder, so a name change was in order.
Otani: Actually, at the beginning, I wanted to add Wonder. Like “Mario & Luigi RPG Wonder”. But while we were making it, “Super Mario Bros. Wonder” came out first, so we couldn’t use it (laughs).
Thanks to CM30 for sending in the news tip!

To be fair Brothership could be a play on words considering they go island to island I haven’t played the game yet so I don’t know if that is already a thing.
Yes, you are right, it is a thing.
Brothership is by far the better name.
Mothership
I still think that Super Mario Bros. Wonder is a weird name, but it still fits well enough for that game. Mario & Luigi: Wonder sounds way less fitting compared to what we got with Brothership
I never brought this type of style Mario game is this an RPG?
Yes! The Mario & Luigi RPG series is a lot of fun with great “single button per character” controls (at least for the early ones). If you have NSO you should check out the Mario & Luigi Super Star Saga in the GBA emulator app.
The game is pretty good!