All articles are at the 2nd level URL. How harmful is a large number of articles?

Question

Search Engine Optimization

On the site, all articles are located at the 2nd level of the URL. (site.ru/ post /)
At the same time, there are several categories. The structure of the site is quite simple. But there are a lot of articles. Articles are user generated content, so every day there will be more and more of them. Does it make sense to switch to /category/post/ or is everything ok?
Are there any negative consequences for SEO? Or the maximum bad thing that can happen - the user will get a little confused.

Answer 1

There will definitely be no negative SEO, on the contrary - if you need to move an article to another category, then there will be no trouble with changing the URL associated with the previous category.
Users don't care about URLs either - they simply don't look there.

Answer 2

As long as you don't move past level 3, there shouldn't be any reason to be concerned.