Merry Christmas and Happy New Year to you, too!
No, I wouldn't say the FP90x is worth $5k (assuming USD). Are you located in the US? If so, you can pick up a Roland RD2000 which has the same action as the FP90x for around $2k on Reverb, or under $3k new. It also has much more control over the internal sound, plus you can use its sliders to control Pianoteq parameters without touching a mouse/keyboard. It also has an integrated audio interface, which is nice for a hybrid setup, where you blend the internal sounds with Pianoteq (or other VSTs).
It doesn't have built-in speakers, but a couple of good 8" monitors will get you plenty of low-end for a very realistic piano sound. Something like the Kali Audio LP8 V2s and some monitor stands would be under $500 and give you much more realistic sound reproduction than the FP90x.
Don't get me wrong, the FP90x is a wonderful piano, but it's not worth $5k USD.