Printing in colour in kde terminal shows very little difference regardless of the intensity requested

For examples for printing in red, you can use :
*’ \e[0;31m’ for Regular color
*’ \e[1;31m’ for Bold color

  • ‘\e[0;91m’ for High intensity
  • ‘\e[1;91m’ for Bold high intensity

6 years ago, it was working as expected on my asus G75VW.
4 years ago, I change my laptop for an asus G731GV. At this times I remark that the difference of intensity was less brillant.
A few month ago, I bought a new computer asus ROG Strix G18 G815LM.
There is practically no difference between the modes.
Are there any adjustments to make?

Any help is welcome.