If there’s a free version of yWorks, that might be a better choice because of their work on orthogonal edge routing algorithms. Also, Tom Sawyer software has an academic version that is free for 1 year. Many years ago I talked with someone that released a commercial product with full orthogonal edge routing, and they said getting an implementation right was far more work than they expected. (That being said, there might be a lot of simplifying assumptions one could make for layered graphs.)
This is an example of an area where open source software struggles, because the problem is technically difficult (probably multiple years of graduate level hacking) and though ultimately many people could benefit, there is no reward system in place to encourage or support such work. All we have is 20 year old summer intern code. I think the intern is now a professor and recently promoted to a named chair at an institution in Southeast Asia. So hard to get hacking help from them now.