So much to dig into with this one! I will look and try to offer more thoughts from my own experience this weekend. Worx has a great support team that you can share this with and they will give you lots of helpful feedback too.

what do the purple markings signify?

For now, the wire that worked well for me: https://www.amazon.com/gp/product/B07G98GDFN/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1