Imo yes, at least 1.
Witcher 1 writing is great and explains what exactly a Witcher is. There's some good lore here that can help understand the general world of Witcher in later games. Do install a speed mod on PC though some parts just are too big.
Witcher 2 helps expand on the world building but I feel like it was less crucial to the whole thing. Also gameplay is clunky (it wasn't good in 1 but 1 felt more like a traditional RPG).
Anyway if you don't there are actual encyclopedia entries in 3 to explain things and people as you play
RS3: UltimaSuende - CE Thread Zone
https://letterboxd.com/BMovieBro/