You will have to forget about them and move on, the last time they added stuff was back in feb, it's been months if they were gonna be back they would've already, I also have lost my plan to read + reading lists, like completely empty (aside from 300+ titles in my already read list) i have moved on and I'm rebuilding my lists with stuff I'm currently reading or want to read, so yea my advice is to move on, and lose hope they aren't coming back.
That means you didn't rate them, sorry twin
Long story short, if you rated/tagged your reads before they all appeared back under already read and now you have to manually move them. But if you're saying you don't see anything at all then you must not have rated/tagged those stories so now they're unmarked permanently. Unless you go find them again
Hii just in case it ever happens again you can use
https://manhwatracking.com/
It automatically adds your reading lists across several sites which stays intact even if something happens on any of your reading sites. It's a browser extension so you go through your reading lists and a small window will pop up for you to quickly change status/rating/comments etc!

Hey guys!! I remember this site going down a couple months ago, but my reading and want to read lists never recovered? My already read is intact.
Has this happened to anyone else and will they be restored?? I have years worth of manwha