Hello Fritz,
SDM is off by default because of security concerns. By default most things are secure by default so as engineer you could make it less secure if you want.
When the webserver is configured in HTTP port 80 is used by default. With ARSim you could run into issues if an other service on your laptop is already using that port.
HTTPS should also work but by default the certificate is then not trusted by your webbrowser. See B&R Online Help: CPU properties - Web server to configure your own trusted certificate.