No worries, it's a common question for me.

I can fly internationally just fine, however my name always gave the immigration officer a headache. Simply because, there's no standard way of resolving it and searching for the correct record of me is painful.

For example

the name on my passport: Steven

My UK Visa: Steven Steven

If I need got to US, from what I heard: Either "Steven LNU"(Last Name Unknown) or "FNU Steven" (First Name Unknown)

Some institutions prefer:

Steven -

Steven .

Steven ,

So yeah, major headaches, especially because my only name is super generic

Since you only have one name, wouldn't it be both your first and last name? Is there a reason you don't input "Steven Steven"?