This isn't specific to Slavic languages, it's the norm for all sorts of related languages or even the same language evolving over time. Think of the etymology of 'nice' or 'guest'/'host'/'hostile'/'hospital'.
Words derived from the same source as 'Loft' seem to universally mean 'sky' or 'air' in almost all germanic languages... except English where it means 'small room near the ceiling'.
I guess Wiktionary might be mistaken, but it says the not-really-so-modern meaning of ‘loft’ is shared among Germanic languages: https://en.wiktionary.org/wiki/loft
Well, the word apparently has a bit unusual etymology:
> The word has been used as a euphemism for "poison" since Old High German, influenced by Late Latin dosis (“dose”), from Ancient Greek δόσις (dósis, “something given; dose of medicine”). The original meaning "gift" has disappeared in contemporary Standard German.
So yeah, the word is the same, it just became divorced from the former meaning.
oh wow i was actually completely unaware of the etymological history of it, but after reading what you said i did some research and confirmed it for myself. thank you for sharing that with me, and for allowing me to turn an unknown unknown into a more productive form :^)