It's surprising how Act-Age is always in that ToC position but its volume-sales are good. Seems like ToC isn't a reliable source...
And same goes for Dr.Stone...ToC top 5 but its sales are mid.
Basing on this ^ I'd like to wait before saying that TSS will be surely axed. Its 1st volume has yet to be released.
To clarify the whole 10 volume thing, it wasn't actually announced that he is determined to only have 10 volumes. He was referring to the concept material, and he even said he has no idea how long it will be. He continued by saying "let's just assume about 10 volumes" and also mentions that he initially expected Naruto to only be 15 volumes, which obviously, ended up not being the case.