I had some free time, so I was ahead of my schedule. As soon as they approve my [PR] (Add obsidian-koreader-sync to community plugins list by Edo78 · Pull Request #738 · obsidianmd/obsidian-releases · GitHub) my plugin can be installed like any other community plugin.
BTW, I only have Linux, so I can’t test it with other operating systems (I’m pretty sure it shouldn’t have any major problems on Mac but I have no idea how it might behave on Windows).
Anyway any feedback will be welcomed