Lol you're over exaggerating for how hard modding is. I can tell you're very much not a fan, but I wouldn't be a hater. I'm not saying modding is perfect, and I never even mentioned Bethesda games are engines. You're confusing me with someone else lmao.
But modding is still a good way to get a "finished" experience. You can't change that fact.
Modding is EXTREMELY hard for Bethesada titles.
It takes months to years to crack their encryption and file types, so that other types of mods can be created. They don't use common file type extensions, so modders have to work on those files at the Assembly level to figure out how data is stored, manipulated and how you can make a file to access them.
Don't believe me? Go harass Caliente for Skyrim, and ask them how hard it was to create Bodyslide initially. Or how hard it was to port CBBE from vanilla Skyrim, to the Skyrim Remaster of 2016.
Once other modders do the foundational work, then it becomes easy to make mods.
Like the Sexlab Framework only came into existence like 3 years after Skyrim's release (2014-ish). It needed so many other foundational mods just to make the barest version work, and back in those days you didn't have physics, reactive body parts, or smooth transitions.
You really do not know how hard modding is. If all you wanted to do was some minor code edits or some scripting, sure easy enough, but most of the really complicated mods took a lot of work from many different modders to get there.