Honestly, I kinda hope it isn't. Partly so that there's another female Belmont,
How can there be "another" if the first one apparently didn't count?
and partly because Sonia was Trevor's mom, while this seems to be his daughter.
Key word: Was.
Then she got Thanos snapped out of existence.
Now, if we want to bring Sonia as she was back into existence instead, let M2 take a swing at giving Castlevania Legends the Haunted Castle Revisited treatment or something? Then I'm all for that, and retract my previous statement.
But as long as that Sonia remains excommunicated from canon, well...