Quite honestly, sniping rules are stupid. None of us own copyright. That's my stance I've kept before and after I started scanning myself. It's a courtesy to avoid mangas that are already being worked on, if for nothing but not wasting each other's work, it shouldn't be a hard rule. If their quality is too low, clinging onto project ownership would instead become harmful to the readers and community.
I don't know how Haevn works so I can't say much about them, but imo I believe you two made the right call. Joining a group and asking to take over a project that's already assigned can cause friction, and I tend to find that there's a lack of trust towards new members, skill level aside. Rather than getting tied down by group hierarchies and policies, going solo can be a better choice at times.
Your version was much much easier to read. The wording made sense and it's much more immersive. Like tempsventeux said, your wording choice felt much more period appropriate. These latest few chaps were especially emotional ones imo, and your translation helped convey that greatly.