First, you should format your code like this for better readability:
~~~js
// Code
~~~
Next, to solve your problem, replace
app.vault.getMarkdownFiles().filter(/* arbitrary code */)
with
app.vault.getMarkdownFiles().filter(/* arbitrary code */).sort(({ basename: left }, { basename: right }) => left > right ? 1 : left < right ? -1 : 0)