@av8r I would suggest that you install this GTK theme “pho-earth-adaptive”, it is a GTK4 theme, hence GTK4 will be installed. This theme will follow the color theme of whatever plasma theme that you install. I see this theme as a GTK theme problem solver. Once you use this for GTK, you’ll no longer have to hunt for matching GTK themes.
Download the theme, and extract it in ~/.local/share/themes/ then you can select it in System Setting → Appearance → Application Style → GTK Application Style (bottom right button)
I just tried it, and Pamac looks horrible for me (and it has the issues all other themes but Adwaita have in Pamac preferences too, so not up to GTK standards / not up to date, I would guess), back to Adwaita.
My personal preference currently: Materia Dark global theme with Adwaita Dark GTK theme.