Dark mode and Ungoogled Chrome

I installed Zorin Core, and played with it. While on Core, I also installed Ungoogled Chromium, and its window match the dark theme I have chosen to have with Zorin, just like it does with the pre-installed Firefox.

I decided to support Zorin's development, and paid to download the Pro version. Well, Ungoogled Chromium isn't dark as it was on Core. It has the grey colour instead. Is that a known bug? Did I dreamed it being darn on Core, and was not, actually?

Chromium, on the other hand, adheres to the set theme.

Can you open Zorin Appearance and check color and accent color? Perhaps it is just a different setting.

Might be a Flatpak or Snap problem, I recommend you install Chromium or Ungoogled Chromium with .deb or PPA for better performance.