china wants the EU to stop funding ukraine, and let russia win the war on their own - this is the most advantageous outcome to china: russia loses military strength doing the fighting, but not enough to collapse, and thus becoming more reliant on china. But still strong enough to be a concern for the west, so that the west cannot focus all their efforts on china.

I don't understand that last part. The US is a big country; it can walk and chew gum at the same time. We're spending some money and attention on Ukraine, but I don't see how it would affect our position on China if we weren't.

I do think that the US is badly mishandling its relationship with China, but it is a deliberate choice, not an oversight.

What would we be doing if we had more focus?

They've been doing that already in the past few years.

Likely they will increase their support. It’s a very short distance to this becoming a China/NATO proxy war.

It is actually weird, when Russia starts a war only to become a proxy of other block in its own war.