I used wallabag and liked it. I stopped when I had to move my server and backed up the data. I installed wallabag again and the backup would not work with the latest version. I had exported it in various ways as well, just in case one didn’t work well but none worked. So that left a bad taste in my mouth. This might have coincidentally happened right in a database upgrade or something inbetween the 2 versions, but the fact that my backup could not be used frustrated me. Still looking for an alternative and am considering readdeck like you. I tried it a while back and did not see a way to export data at that time (I think it could have been done from command line though?). Been over a year since then so maybe that has changed. Right now I am using Shaarli for bookmarks and it works. It doesn’t stick for me like wallabag did though.