The first few chapters seems nice with lots of potential. I really enjoy this short manga. But I get why it got axed because there are many flaws in the plot:
1. characters are not built well and people to people connection is very shallow and superficial for some reason. There are so many characters that could be explored and connections to be built. Like the friends Wayne, the Marquis' family, the captain, his team, the royal family. I feel like these characters are just NPC.
2. I like our MC here, but his isekai background could be ulitilized better. He could implement his experience in modern military to this. I guess that's something the author tried but not detailed enough due to lack of research. He's also quite NPC like. He don't have characters development and no struggle at all. Everything come easy and convenient to him that has nothing to do with his past life memory.
3. The pace is too fast. He raised up his ranked and settle down so fast. I feel like there's nothing else for him to fight for anymore. If the pace is a bit slower, focus on his military tactic, deepen more human connections instead of erasing them (his best friend just faded away for example), and later to slowly establish his own territory, it would be a very great manga.
Anyway, maybe the author is amateur and just want to draw something short to try it out. It does have its own charm and has hooked me while it last.