LOL, I'm not sure if this is the right place to ask, but how do I create a "next chapter" or "previous chapter" button? I thought wordpress did it automatically, but when I added a new series, the "next chapter" would be linked to the newest post. And then I've seen other websites having their buttons linked correctly. Do I have to add them manually? Or is there an add on? Thanks in advance!
There are probably addons for it, but otherwise it's just manual. Having left-aligned 'Previous chapter' text hyperlinked with the URL for the previous chapter, and then a 'Next chapter' right-aligned. You can make it fancier by adding arrows or bolding it or whatever. It sounds like you're using Wordpress posts for your chapters rather than pages. Pages can be a bit easier to work with since they can have fully configurable URLs without the date, and you can set the chapter to have the novel's table of contents as its parent page to make things neater. Giving you uniform URLs like blog.com/novel-name/chapter-1, blog.com/novel-name/chapter-2 etc rather than blog.com/2020/12/09/novel-name-chapter-1, which also makes it impossible to create the next chapter link before the next chapter has been created. You can then use posts on the blog's front page to link to the pages when chapters are released. And unlike posts, pages don't have the automatic links at the bottom going to the previous/next post for the site, which as you've found can be a different novel.
I'm not sure how much you know about programming (or how much wordpress allows its users to do), but maybe you could make a list with the chapter-links and have the buttons point to the next (or previous) element in it (or be hidden if there is none).
If you're on wordpress free plan, it is likely that you'll have to add the links manually since the free plans don't allow much for users to configure the code on the site or have add-ons (unless business plan). It's not a problem if you're only translating one series but the posts will jump if you have multiple. Years ago, I did ask Wordpress if they had this function and the answer is no. The sites where you've seen the automatic next/prev chapters button are likely to be self-hosted sites. For such sites, you can use a plug-in or code the buttons to toggle within the novel category. There may be work around to this but I'm not sure, so hopefully you find an alternative method since manually linking chapters is a huge pain in the ass.
Posts can be pre-emptively linked, eg domain.com/food-chapter-2. The link follows the post's title/permanent url (which can be manually edited if need be). Wordpress.com's premium plans also don't allow plugins. I presume there's a way to code in some automation so you don't have to change the links every time you post, but I don't the braincells to research past the articles of "you can maybe do this but I'll explain how and not show examples of code and where to implement them on a limited WP site".
If you are on free wordpress, you will have to link it manually yourself. Like writing this at the bottom of the chapter -> Previous | TOC | Next Then put links on the keywords.
Manually. It's a pain in the butt, but I don't want to pay just for a button. There's a button block, or you can do as @Solus pointed out. Sometimes the alignment is thrown off after wordpress.com updates (I am still editing through 40+ chapters to re-align all of my buttons), so I recommend keeping it simple. I have a chapter template that stays in my drafts folder with premade buttons that I just have to add links to. I just have to remember to "Copy Post" so I don't type over the template and have to make a new one.