Unity temperature problem on Ubuntu players when connected screen is UHD

I have an empty project only with a Canvas where I draw a circle and a text that I'm building on 2017.4.40f1 (also tested with 2020) for Linux players connected via HDMI. It looks like this:

The Linux player are mini-pc Intel NUC7i3BNK running Ubuntu 20.04 and the Screen is LG43UL3G (UHD 60Hz), portrait orientation. There isn't desktop configured so everything is launched via command line.

The Player.log shows:

Desktop is 2160 x 3840 @ 30 Hz
New context 0x399ea10 created with attributes:
Initialize engine version: 2017.4.40f1 (6e14067f8a9a)
GfxDevice: creating device client; threaded=1
Renderer: Mesa Intel(R) HD Graphics 620 (KBL GT2)
Vendor:   Intel
Version:  4.6 (Core Profile) Mesa 20.2.6
(...)
Default vsync count 1
requesting resize 2160 x 3840
Using native desktop resolution 2160 x 3840
requesting fullscreen 2160 x 3840 at 0 Hz
Desktop is 2160 x 3840 @ 30 Hz
UnloadTime: 5.338000 ms

And if I print the screen resolutions with xrandr from linux terminal I get this

Screen 0: minimum 320 x 200, current 2160 x 3840, maximum 16384 x 16384
DP-1 connected primary 2160x3840+0+0 right (normal left inverted right x axis y axis) 1600mm x 900mm
   3840x2160     60.00*+  50.00    59.94    30.00    25.00    24.00    29.97    23.98
   4096x2160     60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98
   1920x1080    120.00   100.00   119.88    60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98
   1920x1080i    60.00    50.00    59.94
   1280x1024     60.02
   1360x768      60.02
   1280x720      60.00    50.00    59.94
   1024x768      60.00
   800x600       60.32
   720x576       50.00
   720x480       60.00    59.94
   640x480       60.00    59.94
   720x400       70.08
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)

As you can see the default screen or system resolution is 3840x2160 and 60Hz. With this resolution, the players overheats and reach 78ºC. If I modify the screen resolution via xrandr --output xrandr | grep "connected"|cut -f1 -d" " --mode 1920x1080 -r 60 then the temperature goes lower than 58ºC. Same player and unity build, connected on a FHD screen, has a temperature between 50-55ºC.

I need the screen to be configured in UHD, if possible, because it shows more contents not related with Unity (i.e. UHD videos or pics). Anyone knows why could be this temperature problem on UHD screen? I've tried different player resolution settings on Unity without success on Ubuntu. On Debian 10 it works better.