Merge 2 maps at specific index - sass

Question

I was wondering if I can merge 2 sass maps at a specific index of the first map.
$numbers: (
"one": 1,
"two": 2,
"three": 3,
"six": 6,
"seven": 7,
);
$more-numbers: (
"four": 4,
"five": 5,
);
#debug map.merge($numbers, $more-numbers);
// ("one": 1, "two": 2, "three": 3, "six": 6, "seven": 7, "four": 4, "five": 5)
Instead, I want:
("one": 1, "two": 2, "three": 3, "four": 4, "five": 5, "six": 6, "seven": 7)
I tried with the list module functions list.index() list.set-nth() but it replaces the index
$index: list.index($numbers, (three 3));
#debug list.set-nth($numbers, $index, $more-numbers);
// "one" 1, "two" 2, ("four": 4, "five": 5), "six" 6, "seven" 7
Even if that worked I am not sure how I can convert it back to a map.
Edit because someone asked the reason behind my question..
I am experimenting with generating utility classes.
u-padding-1: { padding: 0.375rem; }
I have already a map with the values:
$padding: (
"properties": (
"-padding": padding,
),
"directions": (
null: null,
"-horizontal": "-left" "-right",
"-vertical": "-top" "-bottom",
"-top": "-top",
"-right": "-right",
"-bottom": "-bottom",
"-left": "-left",
),
"values": (
"-none": 0rem,
"-tiny": t.rem(t.spacing(tiny)),
"-small": t.rem(t.spacing(small)),
null: t.rem(t.spacing(base)),
"-large": t.rem(t.spacing(large)),
"-huge": t.rem(t.spacing(huge)),
"-auto": auto,
),
) !default;
Now instead of manually adding all the utility key value pairs in the $padding->"values"
"-0": 0,
"-1": 1,
...
I generate them with a while loop and merge them. That would not be an issue but I need these utility classes to be added just before the keyword values like auto, full, etc. for cascading reasons.
I don't want to add another key value pair to my map, for example
"keywords: (
"-auto": auto,
"-full": 100%,
....
),
because I also generate responsive classes and it gets messy.
This is an example of a partial file.
#use "sass:map";
#use "sass:math";
#use "../settings/index.settings" as s;
#use "../tools/index.tools" as t;
$margin: (
"properties": (
"-margin": margin,
),
"directions": (
null: null,
"-horizontal": "-left" "-right",
"-vertical": "-top" "-bottom",
"-top": "-top",
"-right": "-right",
"-bottom": "-bottom",
"-left": "-left",
),
"values": (
"-none": 0px,
"-tiny": t.rem(t.spacing(tiny)),
"-small": t.rem(t.spacing(small)),
null: t.rem(t.spacing(base)),
"-large": t.rem(t.spacing(large)),
"-huge": t.rem(t.spacing(huge)),
"-auto": auto,
),
) !default;
// Populate map with values
$margin-arithmetic-progress: ();
$m: 0;
#while $m <= (t.strip-unit(s.$global-baseline) * 5) {
$converted: t.rem($m);
$margin-arithmetic-progress: map.set($margin-arithmetic-progress, "values", "-#{math.div($m, t.strip-unit(s.$global-baseline))}", $converted);
$m: $m + t.strip-unit(s.$global-baseline);
}
$margin: map.deep-merge($margin, $margin-arithmetic-progress);
#include t.generate-classes($margin);
#include t.generate-responsive-classes($margin);