colors in gnome-terminal

Hello,

On debian bookworm with gnome, screen removes fancy colors, e.g. the
following script from <https://github.com/termstandard/colors> which
is supposed to print a rainbow pattern, does not:

awk 'BEGIN{
    s="/\\/\\/\\/\\/\\"; s=s s s s s s s s;
    for (colnum = 0; colnum<77; colnum++) {
        r = 255-(colnum*255/76);
        g = (colnum*510/76);
        b = (colnum*255/76);
        if (g>255) g = 510-g;
        printf "\033[48;2;%d;%d;%dm", r,g,b;
        printf "\033[38;2;%d;%d;%dm", 255-r,255-g,255-b;
        printf "%s\033[0m", substr(s,colnum+1,1);
    }
    printf "\n";
}'

If I screen, ssh into a bookworm vm, and run screen there as well, the
rainbow pattern prints fine.

Please help me in figuring this out.

Regards,
Nikolaos Chatzikonstantinou