Damn, that was hard! I think I only won because I messed up my strategy at the end.
I will probably be posting here a short-ish write-up of my RL1 run later this week for anyone interested.
All Remembrances at RL1 defeated
I can't even beat radahn at RL 450 (it is NG+4ish). Just feels like the damage output from him is constant. With a fair percentage being unavoidable and very few windows for attacking.
Granted I only tried like 50 times. Which is not that many for me, for example hollow knights path of pain took me over 600 tries the first time.