How can I replicate a legend like this (example in post), preferably within arcGIS Pro or another free, open source software?

[MDB_GIS]

I've been working on an updated road map and I'm 99% finished. The last hurdle I have to clear is figuring out how to wrap a very large legend around various map elements on my layout. I would like it to look something like this. Specifically, some columns need to be taller than others in order for it all to fit. I used to use Adobe inDesign for this, however I no longer have access to that software at this job. I've spent most of the day playing around with it in ArcGIS Pro and excel and I have not been able to replicate it. Any advice is greatly appreciated.