I agree the EU actually stepping up and entering the war in a serious way would tilt everything in Ukraine's favor.

The problem is they just won't. The most important members of the EU (Germany and France) are in shambles domestically and turning far right. Both have little desire to stick their necks out to support Ukraine any further and are likely turning the opposite direction.

Also, Russia has nukes. Nobody wants to provoke that any more than necessary. If Europe weren't a feckless, fragmented military vacuum things might be different, but nothing about that appears to be changing any time soon.