Game runs smooth for me, High settings, I have a ~5 year old video card and 10 year old machine. Dunno what the issue is. Maybe people are getting Ray Tracing turned on by default?
Its exactly the same issue as with Malenia but dialed up to 11. If she chooses to spam the dance you lose, if not you win.
Turn off lock on and run away. That's it, that's how you avoid it.
Lion was easy with the standard cheese of 'letting the NPC summon tank it.' I have 52 Vigor and moderately defensive setup (I use the Physical resist talisman all the time and the elemental one for this fight). Beat him second try by switching to Blackflame as Holy damage didn't seem that good.
I tried joining co op fights and yep, 95% of people suck. Just stop trying to fight it head on. If it's targeting you, go defensive and circle around it until it loses interest. It's one of those classic Fromsoft bosses that just likes to thrash around constantly and half the time you can't even tell it's supposed to be attacking. But again the game gives you tools for this, use them. I had more issue with the Tree spirit in the poison water. Also, yeah, 100% not needed to be fought right away. I had 4 Scabra-douche blessings and the damage seemed manageable. The grab is a 1-hit kill for everyone I saw which I agree is pretty aggravating. Just don't get hit, bro.