EUV and DUV are totally different . They can be developed concurrently.It's still lagging, this is fact. China can't even produce proper DUV machine let alone EUV and still want to buy it from ASML and Nikon. There are many other semiconductor equipment that still dominate by US companies like LAM research etc. And I dont want to talk about software that dominate by android and ios.
We will see soon this year China DUV system is a success or not. If not keep working on it. It just take time.
It take times to develope meanwhile buying from ASML allow them to wait for indeginous development