There’s also not much point in using calamares? If you need to configure your system, you need to edit your config manually anyway, so just do that from the start. There’s little point in hiding from the complexity that you must face when using NixOS.
(I’ve also never seen anyone “praise” the NixOS Calamares installer, FWIW, just people who prefer it due to their habits on other distros.)
The manual equivalent has been discussed before, e.g. NixOS automatic unattended offline installer USB stick, More airgap questions - #13 by kotatsuyaki, Using NixOS in an isolated environment - #23 by ejpcmac, etc.