There are multiple ways to decompose Chinese characters:
|Decomposed into the different...
|historical character combinations
||有 ← 𠂇 + ⺼
||有 ← 𠂇 + 月
||有 ← (一 + 丿) + (二 + 冂)
||有 ← (一 + 丿) + (一 + 一 + 丨 + 𠃌) etc
The "etymology" and "orthography" are often but not always the same, since writing of characters (especially shorthand of combined ones) has evolved a lot over the centuries, the components that make up a modern character may be completely unrelated etymologically to the original characters combined to create it.
E.g. while 犬 looks like 大 plus one stroke, they actually derive from independent symbols which (when simplified) have a similar appearance:
This is somewhat analogous to how e.g. woodchuck in English looks like it comes from wood + chuck, but is actually from the Algonquian word wuchak.