Have you read Discworld? It’s a bit more fun than The Witcher but has similar twists on traditional fantasy and magic ideas
Absolutely not an appropriate recommendation given the details in the request, but a correct one nonetheless.
Prince of Thorns by Mark Lawrence is the first book of a very dark trilogy.
I will also add this, even if it doesn’t match the request, but because it’s so weird and funny: Shades of Grey by Jasper Fforde. It’s about a quite absurd society where people’s social status is determined by their ability to perceive colors. And they are not allowed to manufacture spoons. Sci-fiish
old school: Forgotten Realms
More games of thrones-ey, but less so: Wheel of Time
Grand but well paced: Stormlight Archive (Brandon Sanderson)
scifi one-shot: Sea of Rust
I have no idea if it’s actually similar, but I googled it and there seems to be an overlap of fans between Farseer and Gentlemen Bastards.
So I’m suggesting The Lies of Locke Lamora! The narrator adds a whole extra layer to the disguises, if you’re into reading by ear
