You should find this article beneficial as it explains how the APFS file system works. It has a section on firmlinks which Apple added to APFS in addition to UNIX style symbolic and hard links.
While you cannot create your own firmlinks there are a specialized form of firmlink known as a synthetic link. Here’s an article about how to use them:
Read the comments on this last link, there’s a few ‘gotcha’ scenarios that commenters made mention of.
I am using synthetic links on my Studio running Sequoia. Previously, from the days of Tiger through Mojave, I had created directories at the root level. These are no longer permitted but synthetic links make a good substitute. The folders/files show up on the root directory but actually reside elsewhere.