You may mean the (player/game) profile [as opposed to the Palace Profile]. If nothing else, you should be able to go to plarium.com in a web browser, and choose log in (top right in browsers, anyways). Once logged in, you are logged in / to the account (and forum) - which is different than the next step (actually entering the game). Agreed: Plarium doesn't make it easy to keep things straight.
[Forum profiles are under https://plarium.com/en/profile - this link gives 404, but if you click on a player's icon within a forum, it takes you to their profile under this URL.]
In browser, clicking on your player icon at top right takes you to your account / player profile - you can go this while still being in the game, from any browser. [It's only that you can't be logged in to the game itself twice - attempting to do so will log you out of the first one. But that's the game itself, you can go into the account / profile more than once at a time.]
Sorry I can't speak to mobile, but maybe this will help you get where you're trying to go, outside of mobile. [And not having to leave the game, or figure out how to.]
Thank you very much, but I have the problem on my mobile, because on my pc it works fine, but on my mobile the currency comes out in $ and I need to change it to € and for that I have to quit the game and that's what I don't know how to do, the only thing I can think of is to uninstall it and install it again and thus be able to change the currency