Have been reading WN of this series for a while now, and I'm so glad I did, it brings back the style of novel that hardly ever saw in nowadays mainstream manga/anime, it's actually a weak to strong type of story, but not in a smooth sailing like those popular manga/novel, mc actually train hard, fought formidtable enemies, gone throught meaningful victories and defeats, heavy behind the scense and plot, despite his knowledge cheat, he still strugging and making effort, and most importantly, he's monogamy (as far as I've read, currently ch510)
It's a type of series I haven't read in a while, since the trend now is about strong/cheat character, but there's still a bit of fanservice content in it (shota mc, crossdress, popular mc, etc)