I have this model I have imported in Blender. The UV map is quite dirty and I have the following texture paint as you can see. However when I zoom out some seams appear where there are separations on the UV map. How can I fix this? Please note that I am very new to Blender.
This looks like the results of insufficient margins in your texture relative to your models' UVs. In the Image Editor in paint mode, if you turn on the Display Paint Texture Paint UVs overlay, you can easily see where your painting is relative to the mesh's UVs:
When you go away from your model, the viewport uses mipmapping to reduce the displayed texture resolution and use less resources. But because your painting margin is too small, the mipmap downresolutions quickly display your texture's white background.
Source: Edge padding - polycount
A first easy way to fix the texture as is would be to just change that white background color to the greyish blue (HEX code #2E394C) you have almost everywhere, using the Fill brush:
For further texture paintings:
Do remember to set a higher Bleeding in the viewport's Sidebar > Tools tab > Options panel:
This will make your brush strokes in the viewport automatically "bleed" by a certain amount outside your meshe's UV islands, reducing the risk of seeing the wrong color when your model is viewed from afar.
If you paint from the Image Editor instead of the viewport, you won't have any automatic bleeding but you can manually paint the margin anyway.
Make sure you always have some paint outside your UVs so to avoid the issue.