Blurry export

Hey all you clever creatives!
So I’m working on some illustrations in Harmony Premium (they are Stills for an upcoming animation, hence the use of Harmony), using the Sketching Pencil brush, on Vector layers (not Bitmap). I had to scale the whole thing up, since the print size required was considerably higher than the basic 1920/1080 I was originally working with (the new size is 7500/4218, in order to keep the same image ratio)
In Harmony there was absolutely no difference in quality between the 2 sizes, but after exporting it (as .tga) and checking it in photoshop, there is definite pixelisation on the contours of the lines, when I view it in 100%.
I had initially found a way of accessing advanced render settings through the Write node layer properties, and was planning on running through a couple of different modes, and seeing whether I found a solution, but I closed the layer properties window, and now when I open it I only get basic settings, which is incredibly annoying.
Does anyone have any advice on rendering clean lines when using a textured brush, or simply on where I can access these advanced render settings (alpha, aliasing, etc) which I seem to have “mislaid”?
Thanks in advance!

If it’s what I think you’re referring to, go into the Layer Properties of
the layer you’re working on and you’ll find them on the “Advanced”
tab. I recommend setting the antialiasing setting to “High” if it’s not
already set that way.

Remember that you can scale the texture of your texture brush by going
into the Advanced settings of the tool properties (Rectangular button with
a triangle on it that’s just next to the visual representation of the stroke
in the “Tool Properties” window.