I was there in May, so it might be a bit different as I expect higher attendance these days. Though as for RollerCoasters, I would start with Krake (that one has low capacity and gets crowded fairly soon). Then I would probably go for deamon as it´s not far from it and is also very popular. Then desert race, colossos. Then Big loop and keep the Limit as last (it was almost empty in the evening, I had express buttler and I couldn´t even use it for it, as there was no que).
From the other rides, Aqua spin was allright, El Sol is also cool, but pretty common, so if you know it, don´t waste your time with it. Definitely go for Scream (I would go there between Krake and Demon). Water attractions are nothing special imo. Bobahn is also fine, if you have some extra time, go for it. Octi and Magic are nice relaxing flat rides bscly for everyone, I would say.
personally, I wouldn´t go there without the express buttler, especially for one day. It costs extra bucks, but it pays off, as you get opportunity to experience much much more. the gold buttler is good enough, but if you can afford platinum, it would be probably better as I expect the park to be rly crowded these days.