Potential improvements to be made to the generated svg code

Lets start by looking at your outputted nixos-logomark-black-flat-minimal.svg, (with a couple of newlines and tabs added for readability

<svg xmlns="http://www.w3.org/2000/svg" viewBox="-1650.8306325798367 -1496.4918977395098 3301.6612651596733 2992.9837954790196">
  <polygon fill="#000000" points="-624.0 249.4153162899184 -496.0 27.712812921102 63.99999999999994 997.6612651596733 -192.00000000000006 997.6612651596733 -320.00000000000017 775.9587617908571 -448.00000000000034 997.6612651596732 -576.0000000000003 997.6612651596732 -640.0000000000003 886.8100134752651 -448.0000000000001 554.2562584220408"></polygon>
  <polygon fill="#000000" points="-528.0000000000001 -415.6921938165305 -272.0 -415.69219381653056 -832.0 554.2562584220408 -960.0 332.55375505322456 -832.0000000000001 110.85125168440817 -1088.0 110.85125168440794 -1152.0 -1.7053025658242404e-13 -1088.0 -110.85125168440834 -704.0000000000001 -110.85125168440811"></polygon>
  <polygon fill="#000000" points="95.99999999999983 -665.1075101064489 223.99999999999991 -443.4050067376326 -896.0000000000001 -443.40500673763245 -768.0000000000001 -665.1075101064487 -512.0000000000001 -665.1075101064489 -640.0 -886.8100134752652 -576.0 -997.6612651596733 -448.0 -997.6612651596733 -256.0000000000001 -665.1075101064489"></polygon>
  <polygon fill="#000000" points="624.0 -249.41531628991848 496.0 -27.71281292110206 -64.00000000000007 -997.6612651596733 191.99999999999994 -997.6612651596733 320.00000000000006 -775.9587617908571 448.0000000000002 -997.6612651596732 576.0000000000002 -997.6612651596733 640.0000000000002 -886.8100134752652 448.00000000000006 -554.2562584220408"></polygon>
  <polygon fill="#000000" points="528.0000000000002 415.6921938165302 272.00000000000017 415.69219381653045 831.9999999999998 -554.2562584220411 959.9999999999999 -332.5537550532249 832.0000000000001 -110.85125168440845 1088.0 -110.8512516844084 1152.0 -2.8421709430404007e-13 1088.0 110.85125168440794 704.0000000000001 110.85125168440788"></polygon>
  <polygon fill="#000000" points="-96.0 665.1075101064489 -224.00000000000009 443.40500673763256 896.0 443.4050067376328 768.0 665.107510106449 511.9999999999999 665.1075101064491 639.9999999999997 886.8100134752656 575.9999999999997 997.6612651596736 447.99999999999966 997.6612651596737 255.9999999999999 665.107510106449"></polygon>
</svg>

All of the decimal precision here is comical, you do not need 13 digits of precision here, you literally have multiple instances of stuff as bad as 255.9999999999999 and 704.0000000000001 I would recommend a pass through svgo to get rid of these

Why are you specifying fill="#000000" when 1: you could do #000 instead, and 2: the default fill is already black so you don't even need a fill attribute. A pass through svgo would also fix this

6 redefinitions of <polygon> when they are all exactly the same shape is a bit wasteful, here is how I would improve it with <use>

<svg xmlns="http://www.w3.org/2000/svg" width="512" height="512">
  <defs>
    <polygon id="hl3" points="-99.5,5 -128.5,55 -94.5,114 -142.5,196 -127.75,221.25 -99,221.25 -65.5,164 -32.5,221.25 25,221.25"  />
  </defs>
  <g transform="translate(256,256)">
    <use href="#hl3" fill="#fff"/>
    <use href="#hl3" fill="#f5a9b8" transform="rotate(60)"/>
    <use href="#hl3" fill="#5bcefa" transform="rotate(120)"/>
    <use href="#hl3" fill="#fff" transform="rotate(180)"/>
    <use href="#hl3" fill="#f5a9b8" transform="rotate(240)"/>
    <use href="#hl3" fill="#5bcefa" transform="rotate(300)"/>
  </g>
</svg>

I would make a pr but I cant for the life of me understand this repo and how it generates stuff, I really prefer the old one

Start by locating the generator that produces nixos-logomark-black-flat-minimal.svg, since the issue does not identify a source file or entry point. Inspect how the SVG is assembled, then verify that the generated output removes unnecessary precision and attributes and reuses the repeated polygon shape without changing the artwork.