Если вас разбудить ночью, вы ведь сможете назвать разницу между GetService() и GetRequiredService()?
https://andrewlock.net/the-difference-between-getservice-and-getrquiredservice-in-asp-net-core
https://andrewlock.net/the-difference-between-getservice-and-getrquiredservice-in-asp-net-core
Andrew Lock | .NET Escapades
The difference between GetService() and GetRequiredService() in ASP.NET Core
This post looks at the GetService() and GetRequiredService() methods of the ASP.NET Core DI container, the difference between them and which you should use