I’d probably say Europa Park. I haven’t been to Cedar Point or Tokyo DisneySea myself, but if you’re looking for “a bit of both”, I’d struggle to recommend a stronger choice than Europa Park.
It is a true chameleon of a theme park which tackles just about every element of theme parking you can think of and executes them all incredibly well. I was certainly blown away on my first visit to the park back in April, and even if it’s not your favourite park, I have every faith that you’d probably really enjoy it. As an added bonus, Voltron will most likely be open by then too!
Also, it’s vastly quicker and cheaper to get to from the UK than the other two, if money and time are being considered. A flight from the UK to Baden-Baden or Basel costs only £100-200 each, while flights to Cedar Point would likely cost at least £500 each and flights to Tokyo DisneySea would likely cost the best part of £1,000 each.
Based on distance alone, Tokyo DisneySea/Tokyo Disney Resort in particular seems like somewhere I’d almost recommend that you don’t visit on its own. Each to their own, of course, but a 12+ hour flight for only a few theme park days (I assume?) seems like a lot of effort. I haven’t been, though, so maybe I’m not the best barometer.