Firstly, props for the effort, idk why people are being rude over you making a modern version after so long without it.

I have tried launching the pack, redownloading etc, and it's even been updated once, but I still can't play.

It keeps throwing an error for " SeaBlockWanne/data-updates.lua:55: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
SeaBlockWanne/data-updates.lua:55: in main chunk "

Tried to catch the error. But I really do not understand how this could happen in the first place..
Can you post what factorio version/other mods you are using? Do you have the DLC?
It would be really helpful. Even if it works now with the update.