Once you put a theme on it won't allow you to use dark mode.
Only thing I can suggest is using anorak theme.
I must be missing something.
What themes are we talking about?
Because I have applied many themes to my Note 10+ from the Galaxy Store, and I use dark mode in my Samsung internet browser at the same time without issue.
What an I missing here?
Is it the Samsung Members app that will not allow dark mode with a theme applied?
Then I see what I'm missing.
I don't use the app.
Are you talking about the Samsung Members app, or just the Samsung internet browser for mobile devices?
I had nothing but issues when I tried using the members app, so I just utilize this community through my browser.
I'm good with that.
Deleted the app, less bloatware on my phone anyway.
So, I can't help you with the app.
But you can easily put your browser into dark mode.
Just go to the three line settings icon at the bottom of the browser and you'll see dark mode in there.
And if you're talking about themes for your phone, Samsung has thousands.
You can either go to "wallpapers and themes" in settings, or just pinch your screen and you'll see a themes icon.
Hope this helps.