From the Kotaku article linked by PCGamer:

According to localization expert Loek van Kooten, one of the main issues is that Silksong‘s evocative but concise writing has been turned into “a high-school drama club’s Elizabethan improv night” in the Chinese versions. He cites the following as an example of how the prose reads:

With nary a spirit nor thought shalt thou persist, bereft of mortal will, unbent, unswayed. With no lament nor tearful cry, only sorrow’s dirge to herald thine eternal woe. Born of gods and of the fathomless abyss, grasping heaven’s firmament in thine unworthy palm. Shackled to endless dream, tormented by pestilence and shadow, thy heart besieged by phantasmal demons. Thou art the chalice of destiny. Verily, thou art the Primordial Knight of Hollowness.

Van Kooten goes on to point out that one of two of Silksong‘s Chinese translators, listed as Hertzz Liu in the credits, had a habit of gloating about their involvement in the game and leaking small details about the development process over the summer prior to its release this week.

I took a quick look at the English dialogue and it reads nothing like the example above. If the Chinese translation is really like that, then the tone is indeed quite different.

Kotaku also quotes the following from a Steam review:

First, the god-awful Chinese translation that everyone is mocking. It’s not just pretentious, pseudo-artistic nonsense—the phrasing and even the localization of place names are an absolute mess. I don’t understand how Hollow Knight’s fantastic, quotable translation turned into this unsalvageable heap of garbage in Silksong. The utterly idiotic localization has even affected the game’s world-building and storytelling, forcing me to guess at character relationships and main plot points. Thankfully, the combat holds up, or else I’d be completely disgusted.

While I can't verify it myself, considering the state of JP→EN translation I don't find any of this unbelievable. The complaints line up in what I see in English releases of Japanese games: Misplaced anachronistic language, altered world building, characters and major plot points changed sometimes dramatically (or even cut completely), not to mention unprofessional conduct by the translation team.