Interpreting munin graph and committed memory
Committed memory is, essentially, all the memory which has been allocated by applications, whether it's used or not. In contrast, the "apps" is memory that is allocated AND used.
See e.g. https://elixir.bootlin.com/linux/latest/source/Documentation/filesystems/proc.rst#L932
FWIW, you're using 85 MB swap, which seems perfectly Ok; most likely the system is just swapping out unused stuff so that it has more space for useful things like the page cache.