Zsolt has managed to build a great product out of (what started as) a small project with Mindmap Builder! A product that is so well integrated in Excalidraw, but what as is outclass several stand alone mindmap tools. With the absolute advantage of being able to integrate the mindmap as a drawing in your PKM tool, together with many other notes.
For me that last thing is one of the highlights of Mindmap Builder: that the mindmap is no longer somewhere on my drive, but that it immediately is integrated in my PKM tool.
For both people with and without experience on building mindmaps I highly recommend to take the Mindmap Builder course. In just a few lessons you get the ins and outs of working with Mindmap Builder as a second nature.