At some speeds, I was having similar problems to yours in terms of the beam wandering. I tracked it down to my acceleration settings. I had increased them in order to increase the speed of my machine, but they introduced the issues that are similar to what I see in your photos. I put them back to V1 defaults, and all wandering lines went away.
As for burning tiles, I’m still struggling. Anything that is largely black and white with minimal shading is fine, but when an image depends on having shades of gray, I end up with something either too dark or too light, and have not found the magic settings that are “just right.” Here are a couple of small tiles from today:
