Time Machine is Apple’s built-in backup software for Mac users, offering an efficient way to keep data safe. However, you might experience issues when trying to copy files to your Time Machine drive. In this article, I’ll explain why this happens and how to address it, as well as other common problems and concerns related to Time Machine. Follow along!
Just my two cents' worth on this.
Whilst the advice in this article is accurate and ok to do, I personally would strongly advise against playing with APFS containers and volumes unless you know what you are doing.
I would also suggest that, if you can, that you stick to using an entire dedicated external hard disk for Time Machine backups and not use partitions.
I’ve been using time machine ever since it’s inception and troubleshooted it many times. It is awesome, but is also complex and can easily break if you mess with it.