First, your search term is actually wrong (to be fair it's Google changing things), it should be
lightest thinnest "homemade" laptop, not the current
lightest thinnest +homemade laptop (yes, I tested this, there are now
homemade included in the search unlike with your original search term). Don't ask me why Google changed this but there you go.
Second, even with this, the results still show prebuilt laptops (the word homemade is in the page, but in the places you don't expect: title of other articles). Maybe there are no homemade thin laptops (link if there's actually one) because I've used Bing and Brave and they also came back with prebuilts.
Edit: oh, jszymborski (https://news.ycombinator.com/item?id=36001836) suggests you to use DIY the next time you've searched as this tends to be the term used in the maker community.
