Serviio

You should be already able to access Serviio remotely if your server is reachable from Internet i.e., by IP address w/out firewall blocking rules.

The DLNA standard does not permit routing across the public Internet, so there is no DLNA client that can do that.

The only way to access Serviio from outside your home network is to either use MediaBrowser, which is web based so any device with a browser should be able to access it, or the ServiiGo app for Android based devices which does not use the DLNA protocol to reach the server. Both methods require purchasing the Serviio Pro license. The free version of Serviio does not permit using either method beyond the 15 day trial period when Serviio is first installed.

Yes, I was thinking to Serviio's MediaBrowser, too.

No, you cannot access Serviio from outside your home network using VLC, BubbleUPnP, or any other DLNA renderer/player. Those all use DLNA/uPnP, which will not work across the public Internet. I already mentioned the only two ways to use Serviio across the Internet: MediaPlayer via a web browser or ServiiGo on an Android device. To use either method requires Serviio Pro, which is the paid version.