Ubuntu configuration for minimal-power headless system

jsc001

Hi,
for a battery-operated system, I want to configure a ubuntu 18.04 in such a way that as many unnecessary hardware components are turned off. On a pentium 4/32 Up-squared board. It is an embedded headless application, so I would like to turn off

• graphics system including HDMI and GPU
• ethernet
• (optionally) USB
• limit amount of available/running cores
• turn off bluetooth/wifi, etc
• reduce clock frequency.
  On some other systems such things can be done in /boot/config.txt (e.g. on RPi).

What would be the way to that on the Up-squared (ubuntu 18.04 with 5.4.0 kernel)?

Thanks!