Wordpress is heavy and slow. The reason it can take a long time to load is like this:
Imagine you have an old computer, you want to use it but it is off.
Now you have to wait for it to boot, which can take a while.
But once it’s booted, you can use it, and when it becomes idle, it responds quickly.
Eventually, it shouts off because you haven’t used it in a while, so the next time you want to use it, you must boot it up again.
What I just described is wp-cron, if you disable it, the load speeds may speed up or slow down, it is completely dependent on how you’re using Wordpress. Hopefully you understood that.