One of the primary complaints in the post is password syncing, and I'm not sure that's a fair knock against Arc since it seems like OP would struggle to switch to any browser that's not Safari (and they say as much just generally in the conclusion).
> I use iCloud Keychain for passwords on all of my devices, and of course, my bookmarks are synced via Safari. So when I tried to use Arc, nothing was in sync.
My experience was much better since I use 1Password. The extension was a little clumsy at first, but I gave the feedback and things were improved in the next release and I haven't had any issues since. Really any third party password manager with a Chrome extension should work fine.
Arc is weird, it's a different way of thinking about a browser. I've personally enjoyed it, but I can totally see why others wouldn't. The tl;dr of the post is "if you just want Safari you'll be happier with Safari" and I think that's a totally fair assessment.