Roslynator VS Microsoft.Unity.Analyzers

There's also this project https://github.com/JosefPihrt/Roslynator that can add even more analyzers.

It does. Nearly every style guide I've seen for any language that allows this prefers this style. I personally prefer it when such structures are needed, but would suggest following it just for consistency and the practical benefits.

Roslynator.Analyzers

The reason I say 'similar' above is that though you may treat it as production code, there are some things in the nature of writing tests that may require different coding standard to be enforced. A good example of this is the RCS1046 analyzer, enforcing names of asynchronous methods to be suffixed with 'Async'; in this case it would be acceptable to override this rule (with an .editorconfig for example) so that you're method name continues to describe the behaviour of the application, and we don't have tests named like public async Task My_descriptive_method_name_async().

You can write Roslyn analyzer but you can also simply use this set of analyzers: https://github.com/JosefPihrt/Roslynator. It has analyzers for both async method not ending with Async and non-async methods ending with Async.

My suggestion is to look into installing Roslynator or Sonarlint. Both are free and work with either Visual Studio or VS Code. With them you can right click on your solution and Run Analysis and it will give you a list of "code smells" and automatic fixes for many of them. They are great tools for any dev.

Roslynator while not exactly as good as full R# does a pretty good job for the analysis and refactoring hints imo. Paired with Intellicode + NCrunch (paid) so far has been a good enough experience for us.

I prefer the second and roslynator would give RCS1124: Inline local variable1 for the first one.

Roslynator.Analyzers

Unity Analyzers: to find gotchas in Unity-based games and apps.

That warning is suppressed by USP0003 in the Microsoft Unity Analysers. In Visual Studio Community they should be installed by the Game Development with Unity package. I'm not sure about Visual Studio Code though.

My understanding is that SetPositionAndRotation is just a shorthand for setting position and rotation on 2 lines. However there are posts that suggest there is some performance benefits.

Don't compare tags like this if (collision.gameObject.tag == "Platform") because it's inefficient: https://github.com/microsoft/Microsoft.Unity.Analyzers/blob/main/doc/UNT0002.md

You can use either regular Visual Studio (including Community Edition) or Visual Studio Code as your editor. I usually prefer the full Visual Studio because I work with other types of projects, it provides good refactoring support and there are some good analyzers available.