Self-Hosted Question...

If I self host this on my server and install from Github do I get all features as if I paid for a plan from https://akaunting.com/plans or are there features missing? Just curious.

Of course not. You should pay for the apps separately https://akaunting.com/apps

The open source (self hosted) is akin to the free online version. The apps that make up the other versions and beyond are not open source and you are charged for those. In some cases, self hosted may cost more up front as a few of the apps you may want to purchase requires the lifetime subscription to use in the self hosted environment. While browsing Apps from inside the self hosted version, the App detail page will tell you if it is cloud only or if you can purchase.