Hello,
1/ Ajax search result depends on server response time and DB structure. Theme sends requests to your DB and waiting for response. So, if it’s slow then try to speed up the server response time. We can do nothing with it.
2/ It search in titles of products, you have only 1 product with the mentioned text in title.
“Search By SKU” can be activated in Theme Options > Header builder > Search, but it will not work in your case, because some titles of products contain same words as SKUs, and it cause a conflict. There is no a ready solution, unfortunately.
Regards