$  PAGER= nix log .#git
warning: Git tree '/home/whovian/.flakes/aaru' is dirty
Running phase: unpackPhase
@nix { "action": "setPhase", "phase": "unpackPhase" }
unpacking source archive /nix/store/czn1ndgzbim47hr5yaqsaagns42854yp-source
source root is source
Running phase: patchPhase
@nix { "action": "setPhase", "phase": "patchPhase" }
Running phase: configureNuget
@nix { "action": "setPhase", "phase": "configureNuget" }
The command could not be loaded, possibly because:
  * You intended to execute a .NET application:
      The application 'new' does not exist.
  * You intended to execute a .NET SDK command:
      A compatible .NET SDK was not found.

Requested SDK version: 9.0.100
global.json file: /build/source/global.json

Installed SDKs:
9.0.203 [/nix/store/j7w50zcrv5rybkj23vqw062zry8gn1wx-dotnet-sdk-9.0.203/share/dotnet/sdk]

Install the [9.0.100] .NET SDK or update [/build/source/global.json] to match an installed SDK.

Learn about SDK resolution:
https://aka.ms/dotnet/sdk-not-found

I imagine this would still be an issue with rollForward=latestPatch due to our dotnet version being newer, but I'd agree (from my non-programming background) that it sounds like a reasonable suggestion.

$  nix develop .#git
warning: Git tree '/home/whovian/.flakes/aaru' is dirty

[whovian@nixos-wsl:~/.flakes/aaru]$ dotnet --version
9.0.203

  patchPhase = ''
    # Remove global.json to prevent build issues stemming from its existence.
    # We're pinning to an SDK version by using Nix anyway, so it's not super
    # important to worry about Upstream's set version.
    rm global.json
'';

So this seems to have worked fine. Thank you again for the thoughts!