Earlier this year Elon Musk became "the world's first trillionaire".*
That wording made me pause.
The use of the word "first" inherently implies that there will be more.
More trillionaires?
I would rather write "the world’s only trillionaire".
"Only" does not imply momentum.
"Only" implies uniqueness. Isolation. Loneliness.
It takes the edge off the statement.
"First" suggests we might want more trillionaires.
* In desperately sad news, Musk's trillionaire status has fluctuated, and shortly after the IPO he lost it.