Custom SIP Softphone on Windows (.Net Core, C#)

We are looking for a custom-built SIP Softphone (PJSip Asterisk extensions) project using .Net 5 and C# to with the following features: 1) Source Code in Visual Studio project using .Net 5 for Windows Application 2) Downloadable internal directory/contacts 3) Simple UI 4) Minimizable to Tray 5) DTMF and Multi-line with hold, conference, transfer 6) Configurable ring notifications 7) Cannot use proprietary/paid license components 8) Completely configurable from web endpoint (can be XML/YAML/text for the extension, server, etc) 9) Code standardly documented in English