I have several videos which are low resolution and have artefacts and blurring. Which free, or budget video program is best at improving the overall look of the video or even increasing resolution?
I suggest looking at this- https://www.fastreel.com/best-free-video-editing-software-for-windows.html I don't know or have time to go through each to see if it has the ability to sharpen video or remove artifacts. In general, increasing the resolution of a low resolution video, may add the kinds of things you're trying to avoid.