From my experience with different iOS apps, you can’t log in to a Mastodon app with a Sharkey (Misskey) account. In most cases you won’t even be able to pick/search for your server name when you go to add an account. Openvibe, I was able to find the server and log in, but then it couldn’t load my profile or any posts.

So right now I’ve got Kimis for Sharkey, Ivory for Mastodon, Bluesky for Bluesky, OpenVibe because I like the unified timeline (but it doesn’t support Bluesky labelers so I’m not 100% on it yet)…I tried SoraSNS for a few days but I just hated the UI and had a hard time switching between accounts in the app. That’s personal preference though, might work better for you.