Permalink structure question: Should I optimize for keywords or URL length?

I typically optimize my permalink structure for posts like this domain.com/category/postname and this has worked well for me in the past. I have a client who currently has this structure domain.com/postname and they want to update it to domain.com/news/postname.

If I am going to go through the process of creating 400+ redirects for their posts, I would normally recommend adding the category in the permalink structure to optimize for keywords, but domain.com/news/category/postname starts to get pretty damn long, especially with some of their posts with longer titles.

My question is whether you would optimize the permalink structure to be the most keyword friendly version with the category slug or if you would omit that for the sake of optimizing for overall url length?

I personally recommend having a simple permalink with only blog post name.