.NET has the problem if being a MS product. It's only relatively recently that they've decided to be fully cross platform and open source. I'm not sure if it's all the way there yet, but it could be a viable option.
Java is fine as a programming language. Java as a web app more or less means Spring. And Spring means XML files and annotations which come with their own problems. Kind of an out of the pan and into the fire thing.
You can get away without using Spring and do quite fine, but there's definitely a risk that if you invest in the JVM ecosystem you'll get hired to work on Spring.
(alternatives like Vert.x, the less-annotation-heavy quarkus, etc).
For Java web dev I actually like Kotlin better - ktor is pretty nice.
Plenty of companies don't care one second that it is a MS product, in fact it is a positive value on their eyes regarding product support and tooling.
First of all there is more to Java Web development than JEE and Spring, which in any case, other eco-systems don't have a mature answer for many of their deployment scenarios and cross system integrations.
XML is beautiful, there is yet a format that supports machine manipulation, IDE graphical tooling, comments, schema validation as XML.
Anyone that praises Rails will be right at home with XML and annotations magic.
Java is fine as a programming language. Java as a web app more or less means Spring. And Spring means XML files and annotations which come with their own problems. Kind of an out of the pan and into the fire thing.