I'm no electrician, but I recently installed a house battery in my camper after researching it ad nauseam, and that wiring diagram scares me. lol
Why is there a fuse on the ground from the battery? and is that inverter just tapping into the line there? and why doesn't it have a fuse? especially an inverter.
And definitely get a fuse block to wire up any ports or accessories like lights to it so they are fused. Essentially every red wire should be fused.
And if you add things like an inverter, and a fuse block, and... then you might want to busbars.