nah,
he and mio are clearly foregrounded but presenting noah as "the" protagonist is just not accurate at all. this story is about this group of people together. not noah and some randos he interacts with along the way.
I mean
He's the one with the titular Xenoblade
He's the leader of the group who makes the big decisions
He's the only one who can destroy flameclocks and free colonies, one of the main objectives
He has the most screentime and we usually see things through his perspective by default
He's literally the chosen one, and in multiple ways to boot (reincarnation past homecoming, reincarnation past moebius, titular Xenoblade bound to him in every life)
He plays the fweeeeeeeeeee instrument that is central to the soundtrack
He's the only character in the party with his own exclusive (and plot relevant) moveset beyond Ouroboros
Speaking of Ouroboros, his is the only one that gets an upgraded (and plot relevant) talent art
His moebius serves as the most visible antagonistic figure, and his interactions with him serve as the central example of the main thematic conflict
Said moebius is also a central figure in the expansion while Mio's counterpart (who already had much less screentime) is reduced to a cameo
His internal struggles get the most focus (and once again serve as microcosm of the main dilemma of the plot) plus the emotional climax of the story
For the last two chapters he's the leading voice of the group in basically every scene except arguably Colony Omega, and even there he and his weapon are the ones who save the day, the rest of the group is mostly nodding along at this point having nothing of relevance to add
The plot literally bookends with him
It's quite tough to say he's not meant to be the protagonist here. This isn't Final Fantasy VI or 13 Sentinels exactly. Noah and Mio are clearly more important than the other four, and out of the two, most of the list above is exclusive to him.