Yep, this is possible using regular expressions in relevance.
So for example:
exists computer name whose (it as lowercase starts with (regex “[a-z][a-z]d”))
This is a very simple regex that simply matches the first two characters with a lowercase a-z, followed by a lowercase d, so would match your naming convention for desktops.
For laptops and servers, simply substitude l or s for d, respectively. Any of these expressions will not care about following numbers, because with the Starts With operator and the three specific character combinations we’re only inspecting the first three characters of the computer name.