Japanese devoicing/dropping probably varies a lot, I think? No idea what the rules are for when there can be full dropping and when there can't, but it seems like it happens more with verbs than nouns? Maybe?
I'm pretty sure I've heard eg. 分かりました
(wakarimashita, "understood") with full dropping as [ɰᵝa̠ka̠ɾʲima̠ɕt̪a̠], but I don't think I've heard eg. 舌
(shita, "tongue") as [ɕt̪a̠] but only as [ɕi̥t̪a̠] with just devoicing rather than full dropping, although I do think I've heard eg. 明日
(ashita, "tomorrow") with full dropping as [a̠ɕt̪a̠] sometimes, so it's probably not as simple as it being an issue of whether it's a noun or not...?
But well, sometimes they're not devoiced at all, like, I'm pretty sure you shouldn't devoice eg. 死体
(shitai, "dead body"), and Wiktionary doesn't indicate it either, so... I have no idea why that is, but I'm not even close to fluent in Japanese; it could be that the explanation is something that's obvious to native speakers and maybe there are very clear rules to all of this. Dunno. My ears are by no means perfect either, so... uh... take this with a grain of salt.