New grill needed - but which one to choose?

With cast iron, you just have to be careful that there are no already burnt spots from grilling - those would then need to be oiled again. Otherwise, no problems with the procedure. I had read the tip somewhere - heating it up after the meal annoyed me too.

Well, that's no problem. Then I'll just turn off the grill when I'm finished from now on, spray a little bit of [Trennspray] and done. Next time, heat it up and burn it off.

Look at the three big brands, namely Weber grill, Broil king, and Napoleon. Possibly also the new Santos series, which is said to be very good as well. Best to thoroughly check all relevant ones by hand, that's the best way. In the price range from around 1000€, they don't differ that much anymore and it depends on the griller's preferences which one you choose. It's best to go to a specialized store that has several brands to be able to compare directly. With the mentioned brands, you hardly go wrong, it’s all a matter of preference.
A cast iron grate has the advantage that it retains heat longer, whereas stainless steel heats up faster. Cast iron requires a bit more maintenance.
A rear burner has the advantage with a rotisserie that you can place a tray underneath the grill goods so that the juices don't mess up everything below. If you want to do rotisserie often, make sure to have a high lid so that the chicken also fits underneath.

The tip with Santos is good, they also provide very good advice over the phone and tailor to your wishes. The Fürst is also recommended.

No idea if the brand has anything for you, but I'll throw the Enders into the mix.

Enders is rather the "Hagebau grill" after all. But you have to see what you want. I also just turn off the grill after grilling and then brush it off properly when heating it up again. The leftovers from grilling (RUB, marinade, etc.) basically season the grate... As a tip, I can add that the Concies (or however that is spelled...) form from the Swedish furniture store fits on it without any problems. Even better, two pieces at the same time. That way, you can quickly have about 10-12 kilos of spare ribs ready for visitors in just 3 hours.

Enders is more like the "Hagebau grill".

Is that so? As far as I know, Enders is an independent company. Weber grills are available at OBI here. That’s why Weber grills are by no means an OBI brand.