Get sub-page menu to display the same regardless of current page depth

Writing a good title for this was tough, so I’m going to explain what I’m trying to do.

I have the following code that was initially made to show the sub-pages of the parent page that goes one set deep. I need it to go deeper. The problem is because of the setup, the way the menu displays is changing when I go to pages that are deeper in the page tree. You can see the behavior here: https://www.dvorakdesigns.com/wp-test/services (the blue menu on the left). If you click through the pages, it changes how it’s displayed.

I would like it to show like this on every page, ideally:

Main Parent

-Sub-level 1
–Sub-level 2
–Sub-level 2
–Sub-level 2

-Sub-level
–Sub-level 2
–Sub-level 2
–Sub-level 2

Here is the code I’m using right now (I wish I could find the thread I initially found it in to give credit!) https://pastebin.com/vkMRQuRF

Hopefully that makes sense. I’ll keep a close eye on this thread to answer any questions.