If you go to https://sv.wikipedia.org/wiki/Ikea the first sentence can be translated to English as: "Ikea Group, written by the company as IKEA Group, is a multi-national furniture company founded in 1943 by Ingvar Kamprad"
Words such as TV started out in upper case because it's an acronym, but once it becomes a normal word, it's written in lower case.
A bit of a meta discussion in a thread totally unrelated to this, sorry about that.
But, I do find the topic of Swedish writing standard to be interesting, so I'll be happy to do my best in responding to your questions, even though I'm not formally a linguist (although I was raised among them)
With regards to your question, I'd write Ios, because it's not an acronym and I do believe that I'm not alone in this. About the version number, I find at least one case of the use of Ios 10 at Svenska Dagbladet: https://www.svd.se/apple-har-atgardat-problem-med-ios-10/om/...
However, it seems to be highly inconsistent, and this is probably caused by these organisations saving money on proof readers.
Why do you keep repeating this? You say you were raised among linguists, but you're getting the most basic tenant of linguistics wrong. There is no such thing as "correct" language.
But more to the point, language allows you to write proper names as though they are registered or defined. It is not incorrect to spell it DigitalOcean, because that's the registered name.
If my name was JoeBob, you don't get to split up my name just because you think English requires it.