Accessing services via desktop


I’ve found references to the libre protocols for services here (Technical Specifications), and IOS / Android setups via theQuickstart Guide.

I’m looking to connect some of the services via existing desktop apps on PureOS (Tootle, Polaris/Pidgin, Quaeternion, openvpn cli, etc.). Is this possible? I’m learning my way around matrix and ActivityPub with these tools, but basic connection info would be great to have. Any help appreciated.