Another alternative to consider is https://www.getdaft.io/ . AFAIU it is a more direct competitor to Spark (distributed mode).
Thanks for the feedback on marketing! Daft is indeed distributed using Ray, but to do so involves Daft being architected very carefully for distributed computing (e.g. using map/reduce paradigms).
Ray fulfills almost a Kubernetes-like role for us in terms of orchestration/scheduling (admittedly it does quite a bit more as well especially in the area of data movement). But yes the technologies are very complementary!