VIM gtk3 does not respect colorscheme/vimrc settings properly

[netneo <netneo%proinbox.com@localhost>]

Hello,

Under both NetBSD 9.1. and 9.2. I have been utterly unable to get VIM to respect my colorscheme settings in ~/.vimrc no matter what I tried. I am reporting this here because it does work on other systems so I suspect this may be specific to NetBSD.

I initially only installed "vim", then uninstalled "vim" and installed "vim-gtk3". In a terminal window, vim will not respect my colorscheme settings. "set termguicolors" in conjunction with "colorscheme mycolorscheme" in ~/.vimrc are not honored in terminal windows, although it does honor other settings such as "syntax on", "set number".

Still, it does display correctly in gvim. You can find a screenshot here to compare: 

https://imgur.com/a/BM0myii

I have tested this with these terminals:

* qterminal
* xfce4-terminal
* py39-terminator

These terminals support true colors and my vimrc settings work fine under other operating systems so I'm not sure what is going on here. 

From the screenshot, you'll see I've gone at some length to find solutions to this, gathering what I could online. Unfortunately, nothing worked.

Could you look into this, please? Thank you.

netneo