Did you find the Connector tool? (hotkey O). It's by no means a full replacement for the sorts of tools you'd get in Draw.io but it's not nothing. It lets you

Did you find the Connector tool? (hotkey O). It's by no means a full replacement for the sorts of tools you'd get in Draw.io but it's not nothing. It lets you create a two-node SVG path with a bit of extra metadata. One or both nodes connect to a special node at the centre of a shape. Inkscape automatically makes that be a straight line trimmed to the edges of the shape(s. You can move the shapes and have the line move too. If you move the path itself it turns back into a regular path. The path is just a straight line as mentioned and there's certainly no routing logic.