It shouldn't really impact it tbh, I added hundreds of mine back in a panic and my already read list returned. There are several possible reasons - non-rated manga are being done later, their focus is rated manga right now, you could've been missed on the first pass which finished last night, in which case it might restore on the second pass which is any time now.
Yes, I haven't added anything besides that one manhwa because I was just confused as to why it was no longer included in my reading list.
Just to be clear though, when talking about lists, we're pertaining to the ones labeled as "I want to read, I'm reading , and I already read" right? And not the other lists where you have a custom title?
Also thank you very much for your reply! It's starting to make more sense to me now.

Hi, anybody here whose account was made in 2021 not have their lists back yet?
I was under the impression that they were restoring older to newer accounts, I've already seen accounts made in 2021 with lists back on their profile already but mine still hasn't come around I was wondering if anyone is having the same issue?
When the site just came back, I didn't quite know what was happening yet so I added one manhwa to my reading list (just one though). Could that be messing up with my account's list restoration?