Nasty lines

[cherrynoize]

I've been using wpgtk for so long and initially setup a script replacement which switches between two different light and dark colorschemes fo Neovim because of this, but now I'm integrating wpgtk more and more because it's such a cool idea and it's really worth the time I spend on it.

Therefore I really want to set up a vim theme as well, but both wal.vim and this theme show these nasty high contrast lines:

What can I do about it?

I'm currently using AstroNvim on top of Neovim.

Edit: also it's important to note those lines are normal (the vertical one in the center is my margin), it's just the colors that are off.