@Franko, it probably doesn't help by posting your problem all over the forum. This is referred to as "Cross Posting" and on other forums it would have you banned. if you haven't already noticed, this is a very quiet forum with little traffic. Thus your persistent posts are most certainly noticed, and possibly ignored.
I'm only new here, but I spent a lot of time on the forum a few years ago. Over the years it's become more difficult to clear cache's, but this probably isn't the fault of Dolphin. As web sites become more complex, browser designers constantly look for ways of storing information to speed up page downloads. Once upon a time you could click the refresh option and the new page would reload - not any more!
Clearing Dolphin's cache is one thing, but I find myself spending more time clearing Browser caches and less time drinking wine. Here's a few things I do - some may help and others may not:
1. Do a Google search for your Browser's cache problems. There are dozens of solutions that may, or may not get you off the hook.
2. Set your browser so that it doesn't cache. The downside is long page loads from slower servers.
3. Avoid criticising the car when you're using the wrong fuel.
With Google Chrome, they have what is called Incognito Mode. This saves nothing to the computer. To use it, hold the Ctrl key and hit Shift N. You will receive a distinctive message and the screen will go grey.
Many people use F5 to clear the cache, but I read that it's actually Ctrl F5. That's a big difference.
Firefox has Private Mode:
https://support.mozilla.org/t5/Protect-your-privacy/Private-Browsing-Use-Firefox-without-saving-history/ta-p/4473
Safari, Opera and others all have similar cache avoidance systems. As I don't know what browser you're using, I'll leave it to you to do the research.
In the meantime, please keep reminding yourself that Dolphin is essentially free and the people who help you are volunteering their services. I think it pays to be nice.
Best wishes
John