We've had good experiences with Lattice parts. Their software tools are free for all of their basic chips. They only charge for licensing when you use the higher end SKUs with SerDes. Example, you can use and develop on an ECP5 or Certus using their free license, but then you need a paid license to work on ECP5-5G or CertusPro chips.
They're not perfect, but they're better to work with than Xilinx. Also, their datasheetd are better than Xilinx in my experience.
If i'm understanding the repository correctly, it looks like each language reads from a file, does some I/O printing to console, then computes the value, then some more console printing and exits.
In my opinion, the comparisons could be better if the file I/O and console printing were removed.
They're not perfect, but they're better to work with than Xilinx. Also, their datasheetd are better than Xilinx in my experience.
Give Lattice a look for your next project.