That is incorrect, at least as far as the manga goes. It is heavily oldschool D&D inspired, using things like dice rolls, vancian magic, and technical arguments for getting the edge. Plus, solid narrative and encounters where the protagonist isn’t OP. The OP specifically chose an octopus familiar, because each limb counts as an action under the ruleset.

This particular manga is closer to Goblin Slayer, Speedrunner, and Dungeon Meshi in spirit. Hopefully, that translates onto the silver screen as well.