If you use a tablet, I have a trick that helps speed up the process for things like this. Even if you just have a mouse it can be done, just more cumbersome.
It does matter how high the resolution is and what kind of texture / grain is in the entire image.
Step one: After applying a curves or levels adjustment layer to correct the contrast, under the effect Noise, select "Dust & scratches" filter on the entire image. Tweak the radius setting just enough to make the lines disappear, while moving the threshold to try to keep the grain / texture intact. Sometimes you need to move these back and forth to find a happy medium, but the most important part is to make sure whatever you do, it isn't smoothing out the image to a point where all the noise gets smoothed out.
Step two: Select "Fade Dust & Scratches" and set it to zero%. So everything should be exactly as before.
Step three: In your history, select the "Dust & Scratches" line (the one before you faded it zero) as the target for your history brush.
Step four: Using different sizes of your history brush, "brush" over the lines and any other items you want to remove. If the settings used in the original Dust & Scratches are good, then you may have a nice clean transition between the filtered areas and the unfiltered areas. basically, you will be drawing over the scratches and dust spots, while avoiding the details you want to keep.
This isn't a one-size-fits-all method, and you may need to hand restore a lot of areas, but it's great for large areas without much detail (while still retaining the nature texture / noise) and for working around detail.
You can see in the example with your low resolution image that the smoothness transition from the scratches to the actual un-retouched image is not optimal, but it is a low resolution image. The artifacts were to large to hide without a very large radius and a small to no threshold. It might be much better with a high res image.
YMMV
CW2V
Edited 2 time(s). Last edit at 05/02/2020 10:03AM by CW2V.