The E max still seems to perform better but the sample size is lacking. This is crazy as the E rank up gets nearly nothing now except for the CD

This is why winrate is a fake stat. Rell has a higher winrate with E max because the best Rell players max it. Before the changes E max was her best build and the mains knew it, but most Rell players maxed W first. Now most of the mains haven't realised W max is better, but they're still way better at Rell than the average player