I think it is technically correct, but has fallen out of use. I would understand the sentence "after translating an omen for the people of Samos, he was freed from slavedom", even though I've never heard the word "slavedom" before. I think of it as being similar to the word "serfdom" which is the condition of being a serf.

I don't think it's a real word. Among the tiny handful of search results, one of the first was a link to a Russian-English dictionary, which is interesting. There was one English-English definition, duplicated word for word on three not-very-reliable looking internet dictionary sites. Most significant of all, there is NO entry for this word in either the Merriam Webster (US) , the Oxford dictionary (GB), or any other 'proper' dictionaries. My guess is that it was invented by a Russian translator at some point, perhaps by analogy with, or as a contrast to 'freedom'. It certainly isn't a word which any native English speaker would recognise.

It sounds like an awkward portmanteau word - maybe because of the origins of its parts? I'd sooner use "slavery", although there is the very specific word "serfdom".

If it is a word, nobody uses it. It certainly sounds wrong to my ear. So I would say it's best avoided.