Try https://vectorizer.ai/ it's main purpose is to convert images (rasters) into vectors (SVG). But it has great line detection and color acquisition, give it a go. Bare in mind that this will only work for images, so you will first need to convert the png into an image.

I know that it seems an odd suggestion, but I had to try different vectorization methods for a project of mine and this one was performing very well with low resolution images. Hope it helps.