Switched to testing and editing my /etc/environment setting the enviornment variable to qgnomeplatform. restarted and opened up Konsole to see that the title bar is white with text being unreadable when highlighted, opened up Kate and its still in light mode, then I opened up dolphin and its broken. Is there anyway to fix this? Any help would be great
Do I need to put this in a specific place or just type it as is in the terminal?
Without export. gtk3 or gnome should work.
Alright tnaks
On GNOME and other Gtk desktops, no variable needs to be set. However, the following can be used:
QT_QPA_PLATFORMTHEME=gnome
See QGnomePlatform: Usage and Uniform look for Qt and GTK applications - ArchWiki
QT apps are still messed up sadly 
Please post the contents of the following file(s) using Preformatted text:
cat /etc/environment
and if the file exists:
cat ~/.profile
#
# This file is parsed by pam_env module
#
# Syntax: simple "KEY=VAL" pairs on separate lines
#
QT_AUTO_SCREEN_SCALE_FACTOR=1
#QT_QPA_PLATFORMTHEME="gnome"
#QT_QPA_PLATFORMTHEME=qt5ct
#QT_STYLE_OVERRIDE="kvantum"
QT_QPA_PLATFORMTHEME=gtk3
# Force to use Xwayland backend
# QT_QPA_PLATFORM=xcb
#Not tested: this should disable window decorations
# QT_WAYLAND_DISABLE_WINDOWDECORATION=1
EDITOR=/usr/bin/nano
MOZ_ENABLE_WAYLAND=1
(.profile doesnt exist)
Remove or uncomment that line as I mentioned above.
Remove that line.
If you didn’t already know, after editing /etc/environment you’ll need to reboot for changes to take effect.
Alright thanks, just so I can learn more, whats the difference between gnome and gtk variables?
I removed both of those lines but qt apps look the same as before
Does not compute. Try creating a new user and see if you can reproduce it. If not, you have some user config overriding something.
gnome is valid, gtk3 is not. The avaliable values are gtk2, gnome, kde, qt5ct, or xcb.
Where did you come up with that, anyway? 
Same issue when on a separate account.
I know Manjaro moved away from qtct but I opened it up just to see what it said and currently it says the variable is at gnome. I’ve tried uploading an image to show but the forum wont let me.
Imagine that. 
What theme do you have set for Legacy Applications in Tweaks? Try Adwaita / Adwwaita-dark or Adw / Adw-dark.
I tried switching to using Kvantum which worked, but the text is unreadable as its grey on black, I’ll go back to gnome and try the tweaks. I had default in both legacy and shell
Kate is stuck in light mode still, every other line in dolphin is white and still illegible (but side bar is fine) and konsole is still stuck on light (the title bar at least)
hm… good question. I used that in my custom AppImages, which seems to work in XFCE and Gnome and also in Ubuntu.
case "${XDG_CURRENT_DESKTOP}" in
*GNOME*|*gnome*|*XFCE*)
export QT_QPA_PLATFORMTHEME=gtk3
;;
esac
So assumed it would be universal for all GTK3 applications and gtk2 works also. Maybe I am wrong here 
Can you point to a list or documentation what values are actually valid? Seems it is hard to find official docs for that. Thanks
Setting it to qt5ct and setting it as kvantum with the libadaiwata theme makes it uniform but sadly the window decorations are stuck on the old one which I really hate.
Update: Setting the Shell to default and Legacy to Orchis Dark with Orchis Kvantum disabling composite effects makes it the most uniform I can get it to be. Editing Konsole profiles is screwed up but dolphin is fine
@TheKarion I am not a Gnome user but I think the idea behind all was to remove qt5ct and qt6ct packages and use QGnomeplatform instead and then the suggested solution by Yochanan should work as expected. Maybe I am wrong . Give it a try, your choice of course.
qtct is still installed on testing and unstable branches, and I don’t think qgnomeplatform is working at all. Hopefully this’ll be fixed soon.