When you're looking at things this old the reality is any DNA found has a very good chance of being from bacteria & other organisms/contamination from the more

When you're looking at things this old the reality is any DNA found has a very good chance of being from bacteria & other organisms/contamination from the more recent than 100 million years ago past. Even if you come up with a really clever tool to find ancient DNA you have no guarantees of finding dino DNA nor any way to filter out the DNA from all the organisms of the past, virtually all unsequenced, that could be contaminants.