Interesting and very sorry to read of your woes with Yamaha or as I often refer to them as Yamahaha.
I am not a fan of Yamaha kit at all despite having a basic P121 myself, it is an OK DP with imo the second best action but the best piano voices.
The DGX on paper is a great DP with arranger features and in the very limited market segment there is only the three makes and models that I know of. Being a Yamaha, I do not think that I could get to like the Menu system, I have never played any Yamaha with an LCD screen where I even remotely think that I would like the Menu system. It is like Yamaha want a batch of keyboard players developing RSI through rampant button pressing such is their dire Menu design.
I am a Korg fan but have not tried the XE20, nor will I as I have played their B2 piano which has the same keybed and (1) the keybed sucks and (2) piano voices are fourth behind Yamaha, Roland and Casio, at least these are imo, subjective yes but the XE would not work for me.
Roll on the Casio S3000, I have briefly played one, it sounds good, looks fantastic, is small and just over half the weight of a DGX. Adverse comments about the action maybe but my playing did not notice anything other than the action of a Roland FP and Yamaha P series were better but not by much.
I know I want a change, the Yamaha P series is to basic for me I want an Arranger or rather I want Arranger features but I do not want one with just 61 keys so I have a dilemma. Do I buy a better DP and a 61 Key arranger or by a DP with arranger features there is not an Arranger with 76 or more keys available for less than £2500.
If I go the latter route for a DP with arranger features I would most certainly go for the Casio.
Life was so much easier with my guitar, wanted a change of sound, just change the patch on the pedal unit and go for it.