T480s displayport not working.

So I bought this used T480s that I want to hook up to a 4K monitor. The HDMI is working but only outputs 30hz, so I got a USB-C to displayport cable but I don't get any picture. I am aware that this model have thunderbolt issues (though I don't see any specific symptoms about DP?), and checking the FW and driver version I have 17.4.80.94 and 21.03, which is newer then the versions that should fix these errors. I have a small USB-C adapter with some USB-3 ports, SD-CARD reader and HDMI and everything except the HDMI that is almost working; the computer and Windows says it's connected but I get no picture.

Is it the Thunderbolt issue I have or is it something else that can be fixed somehow or am I completely screwed in getting 4K60 output from this Thinkpad?