Dark mode with full use theme?

[zxcvbnmlp]

Is there a way to fully utilize a theme while having dark mode enabled? Alternatively is there way to have apps think I'm in dark mode while light mode is enabled? I love having a theme and would happy get more but hesitate since I have to have choose not utilizing all of a theme or having eye strain with so many apps that dont have the manual option.

[meself]

There are different themes which will change the look if you will my brother has a dark theme on his phone but dint think it's in dark mode