Structure
What are the elements that make up this word's structure?
To decide if a word is related to another derivationally, we must first look at the elements that compose a word's structure. Words can be related through shared bases. The base is the kernel structure from which we can affix to create different forms of the word. For example, we have the base press. We can affix impressive. Or we can affix pressure.
If ubiquitous, then pause and think about how our word sum would look before you read further.
ubi + quit + ous
That suffix delicious and continuous. It's that first proposed element that I'm unsure about.
So let's look at the entry in Etymonline, an etymological dictionary that will help us see the history of this word. The entry tells us to see the entry for ubiquity. Clicking on that entry, I learn of a theological connection to the word. In Christianity, God is said to be everywhere. The origin of that first element is ubique, a Latin word for "everywhere." Reading on in the entry, that can be further analyzed to ubi and que. So, we have a few options here:
ubi + que/ + it + ous
ubique/ + it + ous
Our base is not Looks can be deceiving.