You know you can just paste mermaid into excalidraw?

It has a mermaid WYSIWYG editor and once the diagram is inserted you can edit it, move objects, add text just like you had drawn it directly in excalidraw.

I usually enter mermaid and then move things around to my liking rather than drawing from scratch.

You can also paste csv in, it's been a while since I've done it but I think it even generates a chart.