Nice work! I like the texture on the leaves – I don’t think it’s in danger of being too realistic. Overall I think there are just a couple things that could be improved:
I took a closer look at the UVs and I think this area needs to be cut like this (or similar) to minimize stretching:
Before:

After

There’s also one branch that is super squished vertically:

You could also use UV Packmaster or something to get a tighter result, but that’s not required since I don’t think there is a free alternative:

Overall though, the texture is just too low resolution for this to be directly in front of the camera. Zooming in shows individual pixels pretty quickly, as well as some serious stretching on the top left branch:

To get more resolution, in addition to just using a larger image, you could significantly scale down the UVs for any parts of the branches that are covered by leaves since those will be barely visible.
Once the texture is the right size, I would try to add more large and small scale details. At the moment you have a good foundation of medium scale details with the voronoi-like bark, but it needs a larger overall pattern that runs up or twists around the tree and a smaller pattern similar to what you started here:

Hope that helps, sorry I didn’t catch the UV issue earlier, and keep up the great work! This is a really tough asset and you’re on the right track.