I can't install the QubesOS 4.3.1 update!

I just got home and wanted to install a software update on my laptop. Now I’m facing the problem that the update won’t install.
The new update is supposed to require a total of about 3 GB, as well as an additional 475 MiB of free disk space.

Now I’d like to know how to install something like this on my laptop.

Question: Why isn’t a software solution automatically installed about a week before such a large update—one that searches for a solution so that the new, large update can be installed later? For example, automatically ensuring that there’s enough free space available.

Can you please paste the error messages you are getting?