I am developing a system with GeneXus in C #, but IIS does not help me much because I think it does not have a command console where I can verify the errors I usually make. As far as I know, Tomcat works with Java, since it was developed in that language, but does anyone know if it works to run web applications with C #?
The tomcat is only valid for java web applications, and not all of them depending on what technologies they use. It would not be worth c #.
If you go to the tomcat website you will see, in the first paragraph of the project description, the Java technologies supported as well as the absence of mentions to other languages.
As you have actually investigated, there is the possibility of hosting ASP.NET applications in Apache Servers (at least from certain versions onwards).
To this end, Apache should be configured with mod_mono, a module that precisely allows Apache to serve ASP.NET applications in two ways, namely:
a) WebForms b) WebServices (of SOAP type based on RPC)
However, personally, before embarking on such a topic, I would first evaluate very well if it truly justifies the effort as well as I would investigate a little about how many implementations of this type are known.
I leave here github link as a source of information