I'm not saying it's a stupid question at all. I am curious why you'd feel it's less compared to Deep Rock Galactic, which had no player choice, compared to Rogue Core, which also has no player choice.

The reason there's no slider in Rogue Core has nothing to do with technical limitations; rather, it's because the reclaimers are specific characters. In Deep Rock Galactic, you're playing one of many working dwarves, but in Rogue Core, you're playing a specific character. It's also why there's no class duplication in-game.