Aside from waiting for ArcGIS Pro 2.4 you can install another edition of Visual Studio like VS2017 along side VS 2019.
The 2 (or more) versions will happily co-exist. They will reference the ESRI SDK that is installed at the time you installed the Visual Studio.
From VS 2017 (probably 2015) you need to install the SDK from the Mricrosoft store via Visual Studio. see ProGuide Installation and Upgrade · Esri/arcgis-pro-sdk Wiki · GitHub
Watch out that you use Open With and select the VS you want rather than Window's automatic selection, it can point to the wring Visual Studio