I do not have experience with homeopathy on cats, though seeing the effects on humans, I would say go for it.
We do have a female cat that was abandoned at birth and a very stressed cat her entire life (6 years), though we never pushed her to become more relaxed if that is possible anyways. Now after being together for 6 years we see lots of improvements in her behavior. When see wants to go outside she let me know and I open a door or window for her to go outside, I will then stay around to let her in, because going out can be from a few seconds up to hours in summer. A little leaf that is unexpectedly moving can be enough to scare the hell out of her and jump inside as if she escaped from this big monster.
In summer she's more relaxed with going outside and that is probably because our back door is open almost all day and she can go in and out as she pleases. We'd tried a cat door, but all cats were too afraid to use it, so it stayed open all day which had not much benefits for us when it comes to letting the cold into our house.
So there might be something going on with your cat Anna, that you cannot solve for her or with her and you might get a grip on it with homeopathy. On the other hand she also might be showing you or Viktor a point, like did something change within your behavior of going out into the world? Cats do watch your behavior and use that within their behavior in their world, so when you then watch their copied behavior you might think something is off with them, when actually they are showing you there is something off with you. A cool interview that illustrates this is the Cat Lover
Let us know how it went at the homeopath.