I am a big fan of open world games like RDR2 and the first one and the GTA games. I also love Horizon Zero Dawn and Days gone but those are all in genres that I enjoy. Stuff like Game of Thrones and things like that just is not my cup of tea. Nothing against it but just is not my thing. Cyberpunk 2077 is day one for me and I know that CDPR are talented devs. Is the game good enough to sort of transcend it's genre?
The following is subjective and based on what little I know about your opinions, along with some assumptions.
+ Massive open world
+ Great writing
+ True choice and consequences without many superficial "good guy" or "bad guy" choices.
+ Lots of sword combat, if you don't mind that.
+ A detailed skill-tree system that should allow you to fight without using a lot of magic. You can just concentrate on upgrading sword skills and other abilities.
+ Most enemies don't use magic, and instead are just monsters or humans.
+ Many side quests and secondary quests don't focus on magic.
+ A fair amount of original monster designs.
+ You'll get an idea of the developer's work before Cyberpunk.
+ The game is really cheap now, so you can get 100 hours of gameplay for 15 or 20 dollars. It's a great deal, and wouldn't cost too much to see for yourself.
- Not using at least some magic might make the game harder.
- Magic is featured heavily at points in the main story.
- All the other things you already know about the game.
Overall, I'd say that if you don't really like fantasy, other aspects of the game might be enough for you to enjoy the experience. If you actively dislike fantasy as a theme to the point where it goes beyond preference, then maybe the quality won't be enough.
Generally speaking what is it about fantasy that you don't like? If you have an issue with magic not being based on science, how do you feel about the Biotic abilities of Mass Effect, or the Force in Star Wars, or the super powers in Marvel movies? Or perhaps it's the time period? If it's orcs and elves, there aren't a lot of traditional fantasy races in the game, although you will see some. I prefer Sci-fi myself, but I don't mind Fantasy, and I loved The Witcher, personally.
If you decide to try it, I hope you enjoy it. If you decide to pass, well, there's plenty of other games out there.