If you don't like the French, the Caro is an alternative. The difference between the two is that in the Caro-Kann you give up a tempo (since you're playing c6 and then c5 instead of just c5 in one move) in order to get the light squared bishop out instead of trapping it behind e6 like in the French. Personally I would prefer the French of the two.
Caro players aren't obligated to play c6-c5 in the Advance.
I find that a lot of a French players think that the Caro-Kann still has the same positional goals as the French, just with a differently placed bishop. But that isn't always the case.
Sometimes the positional goals overlap. Other times, they are quite different. A lot depends on the player and their choice of lines.
For example, this is one of the main lines against the Advance:
We can see that it varies quite a bit from the usual French Advance.
Here, Black doesn't play for c6-c5. Instead, Black is looking to attack on the kingside, in opposite-color-castling fashion (often by prying open a file with f7-f6).
If you're going to learn only the Caro or the French you still need to/absolutely must gain some level of familiarity with the other one--not be an expert, but be aware of some key ideas. The structures frequently shift from one to the other and there are many ideas in common (e.g., breaks with ...c5, sometimes breaks with ...f6, White playing Qg4, the placement of Black's light-squared Bishop, dealing with the pressure created by White's pawn on e5.)
Where can you get some of those key ideas in a relatively abbreviated form? I'd recommend GM Mauricio Flores Rios book Chess Structures: A GM Guide. He looks at many structures. But he does compare and contrast the C.K. and French structures. And for each he provides some thematic ideas for a variety of specific structures within each opening. I think it may even be available on Chessable now, which makes it easier to use in some ways. I have so many notes and highlighted points in the book that I don't think I'll get the online course.
If you want to learn the French, after you get the basics out of the way then I highly recommend IM John Watson's books on the topic. Again, that's after you become expert in the opening. John has been playing the opening since the 1960s and I found his latest on the French insightful, but VERY heavy. My takeaway was it pitched to the master and above level who already specialized in the opening.