Do you have some advice on how to evoke feeling of harshness in the setting without making it caricaturally grim or simply stingy with resources? Something like tolkienesque First Era Beleriand with inaccessible gods and great danger nearby but with less superpowered elves and less focus on nobility?
Are you looking to make a setting with the Good People being in a long term war against a Dark Lord and its armies?
I think making the evil armies consist of people who are either willing or at least compliant to erase whole countries even though they have the capacity to refuse or resists would be a much stronger start than the enemies just being monsters who are not able to behave any differently.
They could even just be humans. There have been millions of people who have enthusiastically participated in such campaigns of annihilation all throughout history. No supernatural influence needed to make them do it.
I wanted to make a setting with somewhat powerful PCs, heroes of the land, but at the same time give players the feeling they need to be that powerful because the world around is tough. Not necessarily magical evil lord-god as the enemy.
I just don't want to make it too grim. I don't want DnD Midnight where all is essentially lost. I also don't want counting every slice of bread because this is not the harshness I'd like to impose.
my main thing at the moment is the untold stories behind Silmarillion - the humans of the East who neither had help from benevolent Valar nor had to endure the powers of Morgoth. The places forgotten by good powers but still messed with by distant evil powers.