I'm considering to get a THINKPAD P52 Laptop.
And want to know if the i7-8850H/Intel® UHD Graphics 630 can run two external 4k monitors?
I want to pair the P52 with two 34 inch widescreens (2x (3440 x 1440 at 60Hz)).
Is it compatible?
I do not believe that will be possible. At 60hz, you can have the integrated flat panel, and an external DP. But, not two external at 60hz.
One of the Intel support engineers will have to confirm. Assuming you can have two external at 60hz, then the real confirmation will have to come from Lenovo with respect to their implementation.