I get that the quality of art is a subjective concept, but I'm confident that isekai manga readers don't know what makes manga good. It's about creating a comprehensive sense of a world through flowing images.
And if I'm using that as my qualifier, this artist does a good, if not great, job with his art. Panels are detailed 90% of the time, building interiors have little touches that convey the nature of the structure, large and intricate panels have a sense of weight as you make the page turn.
All of these things are signs of an artist that really cares about what he's drawing. I think the story is quite a cut above average just by having a somewhat self-aware protagonist.
If I was forced to rate this, it'd be a solid 6. Really good considering most isekai get a 3-4 for me. It's still nowhere near the league's of Moon-lit Journey or other 9-10 star quality isekai stories.