I actually don't know about this since I specialize in traditional and only doodle on my phone, what is artifacting?
So quick lesson on data storage formats for media (I know how this applies more to audio than images, but same general principles apply); they basically fall into two categories,
lossy and
lossless. In
lossless formats we store ALL of the possible data, high precision so we
exactly recreate the original thing 1 to 1 with the highest filesize since we have to store all of the data. In
lossy formats, we go for
good enough with less precision but generally a result that's identical to the human eye/ear with a lower filesize. A lot of the commonly used formats are
lossy as computer scientists like to take shortcuts whenever possible (and filesize used to be a lot more important than it is today).
I shall use this image to demonstrate:

Now let's crank that JPEG quality down to 50%.

There's a few minor changes but unless you're overlaying or looking at them side by side you're probably not going to spot any differences. But if we go to 25%...

We've lost a lot of data and precision; those clean lines aren't quite so clean anymore and color transitions are nowhere near as sharp as they used to be. And if I were do to something like this:

Welcome back to the 1990s and a thousand color palete. Now, for the artifacting Emily has it's sometimes hard to tell where exactly the problem lies. In some images,
it's from the source image because she's using poorly converted videos, low quality images and upscaling them. In others (like her streams) it could be the YouTube compression striking again or it could be that her bitrate isn't high enough to get a consistent accurate depiction of her screen in that moment in time so artifacting occurs. It could also be a filter she's applying that's exaggerating something that wasn't quite so visible until it was enhanced by the filter.
TL;DR - Digital can and potentially will take shortcuts unless you explicitly tell it not to.