Hello Shengke,
I'm really not sure how to answer this...
I'll do my best:
1.
With SEF enabled, joomla articles in IT particles are leading to 404 page - Our Quickstart packages as well as
the demos of our templates come with SEF enabled by default. As you can see, there are no issues at all.
Shengke, mate... our particles have absolutely nothing to do with the routing. The routing comes from Joomla and the way you have configured your website/menus.
2.
To deal with the issue, I have to create a hidden menu item that links to the category the articles belong to as Category Blog page or Category List page, or directly create a hidden menu item for the articles respectively. - well, this is exactly what you need to do. I mean, you should always have a properly configured site structure, which is a properly configured menu structure. This is how Joomla works - it is a menu-centric CMS, the most important thing in any Joomla website is the Menu - it defines the site structure, it defines the URLs, you assign modules to menu items, etc.
But even if you do not have a Menu Item for your articles, then our particles will still open the articles properly.
But the articles will be opened on the Homepage and will have a strange URL.
This blog post explains everything in details.
Here, have a look at
this video that I recorded for you. It shows the things I explained above.