I'm using C# and Java professionally. I've been using for a long time while I'm newish on C#. Also I'm on a older version of .net vs. a modern Java. Honestly to me the language doesn't feel that great. It always feels sluggish, to work with, like I'm fighting against the language. And then there is the ecosystem, Spring Boot is just such a breeze to get a web app running with all the integrations you could ever want being just there. Add in Lombok and Apache commons and it's a real pleasure to develop in Java for me.
The ecosystem is nowhere near as mature though. I don’t work with either anymore but back in 2017 I made the switch from C# to Java and it felt like a breath of fresh air when it came to the maturity and capability of JVM tooling compared to what’s available for .NET.
Try JetBrains Rider, and be sure you are using a recent flavor of dotnet. When I migrated past 4.x to 6 of the .Net ecosystem, it dramatically improved my ability to work and deploy in C# with their rather delightful build system.
For example, in the Monogame game library, you can build a self contained binary for Windows, Linux or MacOSX nearly effortlessly with just a single command line.
The ecosystem is certainly more mature than many smaller languages, but it is still in a different league than Java’s. Most of it is not too great copies of the corresponding Java library, often being made by Microsoft only, with plenty of paid options while in the java world all of it is open-source and free, while offering a much wider selection.
Also, you will find a java library for that random new tech you want to use, while it is likely missing for .NET.
