If you need more than 16k, just press Windows Key + R, type regedit and hit Enter.

Then navigate to:
Computer\HKEY_CURRENT_USER\Software\I1\Final Upgrade

There you'll find these entries : maxStationSize and maxShipSize.

Double-click on the entry you want to change, and on the right side select Decimal instead of Hexadecimal.
If you've set the value to 16000 in-game, you'll see the number 16 here – because it's stored in hexadecimal by default.

I personally set it to 64 and haven’t had any performance issues with my 5800X3D CPU.