Hello mustard
The best board for beginners and for ease of use is the T2 (Unless you go for a used Technics which leaves the T2 OS for dead) however the easy operation is also its downfall, in that you have limited editing features onboard.
Roland’s need some user input to set up, but once done you can get one hell of a sound. (I would suggest E80 rather then G70)
The Korg models are the most balanced of the boards you mention, but the OS can be difficult to get into. (Well worth the effort though)
My personal choice would be one of the low end boards that you have your area, as these will give you the experience, and also allow you to focus on what you like and dislike, thus making your next keyboard choice a whole lot easier.
Hope this helps

Bill
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English Riviera:
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