Hey, I've recently began learning .NET core coming from unity/elixir development. So far the experience was great, and I've began building an API with it. Here's the github project: https://github.com/mattdevelops/ays_api . While building I've come with some concerns that I'd like to get help with:

• Is it really practical to put all of injection code into the one Startup.cs file ? It's starting to become big and just doesn't seem right to me.
• How in the hell should I integrate test this application ? I've been surfing through a lot of microsoft explanations, but I couldn't get any to work.
• Is there better way of doing my routes ? I've noticed repeating route names. Maybe there's some kind of way to input the v1 version into the routes, instead of hard coding ?
• Due of simplicity I've integrated auth0 authentication, however is there any better alternative and more microsoft environment friendly ?
• Due of never doing any much web stuff before, I'm feeling that there's something wrong with my DTO classes, am I doing them right ?

• Are my tests any good ?

• Are there any good open-source .NET core Web API projects that I could look into ?

Thank you ! Loving the experience so far !