I actually ran into a problem when following your instructions in the Excel spreadsheet. It's been a while since I've done this, so I can't remember how to do it. The problem for me occurs in the "copy" instruction step after filling out the columns for a pack.
| ReadOnly: | ~/.local/share/flatpak/app/com.lixgame.Lix/x86_64/stable/ someHexChecksum/files/share/lix/levels/ |
| Writeable: | ~/.var/app/com.lixgame.Lix/data/lix/replays/ |