From what i know yes you can add new stuff
Are they recovering our lost list?
Yes, they are ( for me it was today)but it'll take time. I had around 2k+ altogether but I have got around 300 in lists for now. This has happened before too so we just need to be patient.
But is the "already read" list the only one coming back?
I haven't got all of them but there are few mangas wch I was "reading" is showing in "already read". Maybe after few more days when they solve the problem, everything will be back to where they were.
Thank god, the lists are coming back, idc if they mix my tbr n read together I just want them back. I do have one question tho, can i add new mangas to the lists. I'm worried that might mess up. Thank you