Minecraft is definitely fun. I have a whole lab setup for my kids and neighbors to play minecraft and they are using Java version with curse forge so they can make endless modpacks. I think you mentioned xbox, so bedrock is definitely an option as well, but it won’t have the free flexibility that Java has.
I personally don’t think that a little gore is the end of the world, especially if you play with them. My daughter picked up D3 when she was probably 9, but I played with her and the gore just wasn’t a focus. Every kid is different though and bunch of boys probably not gonna gloss over that.
One you might consider is Fallout 76. It got a bad rap at launch, but it’s a great game and surprisingly has one of the most wholesome gaming communities ever (probably because most of the trolls gave up early on the game when pvp was mostly removed). There are options to turn down blood as well if that’s a concern.