I use both a one and a two-handed topspin backhand, plus a one-handed slice.
It takes me a fraction of a second longer to set up and execute my 1hbh, so if I'm fighting off a deep drive or looking to hit an aggressive bh return of serve, the two-hander is what works for me there. Any other rally ball will be my much more accurate and dependable topspin one-hander. I'll slice if the ball is really low, way out to my backhand side, or even if I want to change up the pace of a rally. I can return well with it, too. Not saying that everyone needs to be like me and use all three strokes, but they all make sense for me and I can use them all well depending on the situation... blah, blah, blah...
It may eventually seem that one of the topspin bh styles just makes more sense in your brain - it comes more naturally for you. If so, that's the one to shore up first. In either case, I strongly encourage you to specifically learn a good slice bh regardless of whatever other style of backhand you also use. I think it's nearly as essential a shot as a dependable second serve.
That indecision you mentioned makes me think that you're still working out your habits with the 1hbh. Eventually you'll have more of a feel for your shots and you'll recognize which stroke to use at almost the instant the ball is hit to you. Keep working on it. When I was first honing a solid 1hbh, I assumed that any ball to that wing would be a slice unless it was clearly in my wheelhouse and I had time to set up my one-hander. That worked great for playing points - no indecision. On the practice courts though, you can try hitting every single ball on that wing as a topspin 1hbh. Also no decision to make, but it will also push you to trust that stroke and handle tougher balls that might make you think twice during a point. It won't be perfect right away, but eventually you'll be able to trust it more often.