Alright, caught up. I would give this a 6 at best. I will say that the author and artist puts extreme effort into making the MC into a complete dud. No distinguishable body or facial features, no expression, no personality, and no life. Yet he can do anything. Yes, it is one of those isekais....
They do contrast it by giving with moderately well drawn side characters with personality (including a dog). In other words, this is the type of manga where the MC is the least distinguishable character. If you want a self-insert manga where you can be surrounded by interesting characters, and you yourself are an overly boring person (like myself), here you go.