Replicate a site to a mobile site with different formatting.

I have been scouring the web looking for a way to replicate a site to a mobile version that has different formatting. I have tried mobile themes, mobile app plugins, tried working with the Multisite feature to see if that could work, and am even considering going as far as just adding a sub domain and having to update two installs every time there is an update, but that is a last resort as it would be very time consuming. The problem with mobile themes is that none of them have worked properly with sub items in the menu and also do not like the table in which the YouTube videos are formatted. This is the first time I have truly tried to mobilize a site and ANY help would be appreciated. The site is https://heedrpm.com. Thank you in advance!