Unfortunately, I'm not attracted much to non-original content
That is your personal problem, not a problem of 7d2d.
By the way, if the game were too difficult for people like you, you could find a mod making the game easier. Would you like this?
I didn't say it's to easy for me. I'm coming close to 1000h since Alpha 15 and since i'm active in the forums and read the dev threads here, changlogs and so on i can adept changes between the major updates pretty fast. So the opposite is the case, i DO USE mods to make it HARDER.
I usually do only one playthrough with each update in vanilla and then do another playthrough with a (total conversion) mod like darkness falls, war of the walkers, ...
But your recursion question is essentially wrong. A new, unexpirienced player usually starts with vanilla and doesn't deal with mods and you can't expect him to do. So the game has to be easy enough that he can deal with it and collect experience. Once someone has dozens of hours into the game and then the game becomes to easy for his taste even with high difficulty settings, THEN you can expect him to look for mods.
So the answer for you is pretty simple:
Either you look for mods that increase difficulty further than vanilla allows, or accept that you are done with the game. There is no third option.
(Besides that there are various ingame settings that increase meta-difficulty you have not used yet, like decreasing loot abundancy or play with shorter days)
And in general, if you weaken the OP mechanics and strengthen weak worthless mechanics, nothing will change in general, but it will become more interesting to play
It's a sandbox. Of course there are mechanics like the trader quests, but because of it being a sandbox it's up to yourself to decide what to do... and how.
You already got suggestions what you can additionally do by yourself, like playing nomad style, not buing equipment from traders but just ressources, and so on.
If you can't do such things unsolicited, just because the game doesn't force you too, a sandbox might be the wrong environment for you.