a desk is a shulchan! Shulchan Avoda is not really used in conversation
It is sometimes used, but then it usually refers to something like a carpenter's work table. We used to say שולחן כתיבה, have we stopped? I wasn't paying attention. We do say מכתבה sometimes.
yes, מכתבה is the word I'm most famliiar with
"The clock is on the desktop"
Why is the ה in front of עבודה and not שלחן?
The ה is called the "hay hayediah", the identifying ה. It tells you what kind of table (שלחן is literally a table)
So if I understand your notes right:"shulchan is any table, shulchan table is more like a workshop table, and desk is either shulchan k'tivá, or miktavá?
Yes, that is how I use it in conversation- shulchan could be my dining room table, kitchen table, etc, whereas michtava is technically a writing desk but used as any desk.