Try to wrap your head around this sense of scale
A nanosecond is one billionth of a second. I.e. every second there are a billion nanoseconds.
A UUID (Universally Unique Identifier) is a 16-byte number used in software. The number of combinations is 2128 = 25616 or about 3.4 × 1038.
Just how big is 3.4 × 1038?
To exhaust all UUIDs you would have to create one trillion every nanosecond...
...for 10 billion years.