It is all going to come down to speed. (The math you are forcing upon each line of Text to move)
The cleanest scrolls happen at a very deliberate, pixel per frame calculation, and if memory serves using even number frame speeds works better.
The last couple of rolls I did were done in fusion, using an expression to calculate that each frame has the pixels moving an even number from their last position. It was a beast of a render at 4K for a 2 or so mInute credit roll, but was as smooth as can be. I used to use the same basic formula in DS, with similar results. Trying to make a roll an exact length like 30 seconds is not the way to go…this is forcing the math on the pixels. Figuring out a pixel per frame speed of say 8 pixels per frame will give you a roll that might be 33 and a half seconds, but it will be smoother.
For broadcast tv with strict timelines for credits…do pages and not rolls.
Glenn