@xeno77 for map, it is still a mystery why the author dont give us a single map yet (nevermind the world or continent, at least the Shiga kingdom). From The detail description in LN & WN, it is impossible to write it with so much detail without having the (atleast) rough map of the continent. My guess is because the LN is still on going and right now they are
(in Japanese release) in journey traveling around the world+saving it at the same time (basically a world tour). So they need to prolong or shorten it according to the sales, if its good, they will add more territory & problem to solve, if its not, they can easily cut it and just go with the main plot. Hence they cant just release a full map. Because doing it will set a "goal" for the story to keep continuing till all the territory/kingdoms all explored (hence making it an "obligation" to fans to keep continuing the story till the end, no matter how many losses they made. For the sake of publisher image, they cant easily axed the story) or even limiting it to just explore the listed territory/kingdom, cant make it possible to add more to prolong the story or even LN exclusive story (hence they cant add more, limiting their possible profit).
When the MC enter a new territory, he always use his "Search Entire Map" magic at the start. So, usually in LN & WN we always granted 2-3 paragraphs of the territorial outline, shape, size, position, population, etc. In this manga, because they get rid most of descriptive internal monologue, the MC dont "tell" all (2-3 paragraphs) of it for the reader, but just limit it to some 3-5 lines.
But, if you want the author confirmed, fan made map:
https://anime.stackexchange.com/questions/46454/is-there-a-map-for-the-death-marchs-world
That it just a map for some part of Oyugoch Duchy territory (along the big river). With no scale, but in LN it is said as big as Japans main island, Honshu.
For the details, yeah sometimes i think that is too much, but believe me man, when you keep reading it, keep swallowing the almost garbage like info, you will know...nothing in this world is 100% garbage. At the correct opportunities, these "garbage info" will show their values, and you will be amazed, like "wait, they already tell us about this long ago. So thats how it is going from the start". Usually this happen at the span of 1-2 volume of novel (10-17 chapters of manga), but some of them is like the Dragon & God lore, foreshadowing in the span of more than 100 chapters.
Edit, or added i must said:
For cheap artist, yeah i feel you. I hope they can hire the "Eminence of Shadow" grade artist. That mangas art is dope.
For generic-like MC, from a writer perspective, i kinda know why they make it like that (boring, almost same like other isekai MC). It is for the sake of readers self-insert. How & why?
That is to make the reader become easier to feel like experience the story first hand. To make them think, the story as some part of their own experience, not just MCs. Its like the mannequin hand experiment. When you see something that look like yourself (either a hand or character that looks just like you), whatever things happen to it you started to feel it too. For men it is like when you see a video of some other man get a hit at the crotch. Even if its someone experience, it is not you yourself that experienced it, you still feel the "imaginary/empathical" pain and start to put your hand at your crotch too. At that moment, you put yourself in the man's/MC place, sharing the same experience.
This thing can be achieved with high possibility if the target audience (reader) is similar with the model (MC). In mannequin hand experiment, the possibility will be lower if the mannequin hand is with the wrong race color. Or wrong/too different shape. For imaginary pain experiment, too much different the physic/image (a real life character vs a cartoon character get hit in the crotch) will lower the probability.
So thats why, to make the story more enjoyable, to make the reader has deeper understanding, to make them feel the same experience as the MC, many stories design their MC as close as possible with their target audience trait. If you want to make story for a child, make the MC a child too, or at least act childish as close as the target audience age's. Want to make story for Japanese teenage schooler? Just make the MC look like them. With nationwide popular hair cut (black-straight-short), average physic height & weight, standard hobby & popular knowledge (games, anime, manga) to make them relevant. Thats why almost all isekai stories MC you see in here has almost same trait.
Want to see sone different MC? Just read Accel World. Good teenage action Adventure story, well enough art, but it has just 1 mistake: the MC is short & fat. Dude, this story released in Japan. They have universal healthcare coverage in there, the percentage of obesity is low. Not many audience/reader can relate and "self-insert" themselves in MC experience. So there it is, a good story wasted.