The Second Coming of Gluttony Overgeared Any novel written by Toika will have MC grinding his ass off.
Please make your reading list public. Tensei Shoujo no Rirekisho - MC reincarnates into magic world with no cheats or magic, only their knowledge, and they are a peasant, not some prince. So its pretty much all effort.
World of Cultivation https://www.novelupdates.com/series/world-of-cultivation/ and this tag may help for novels: https://www.novelupdates.com/stag/hard-working-protagonist/
Also is considered equivalent to 18 year old humans by his race,also toika protagonists do have cheats
https://www.novelupdates.com/series/genjitsushugi-yuusha-no-oukoku-saikenki/ -summoned hero with no cheat abilities, just slightly above average intelligence(by our standard). Works extremely hard to run the kingdom