As the title says, can't research Deuterium Fuel Reprocessing (also thorium i think), i've read in the forum that this was a known issue in previous version, how do i fix this?

I've not been able to reproduce this issue. Can you create a new game, save it, then upload that save file for me please? I'll then be able to sync to that file, getting your exact mods and settings.

I've tried to create a new game, but both the technologies are available.
I've uploaded both a new world and the one i'm currently playing in
new: https://mega.nz/file/LspiBbCC#UwS08qmkw_5-mv1ddPnbXgeYRXxgKD_JX1PKE9Milo4
current: https://mega.nz/file/j5oBDChQ#c8pw7EpT60rij8fKzkH2zupRu_BxoholeaBgdpwoDQ0

Maybe some update broke them? I've had to update both seablock and Angel during my playtrough.

Yeah, it will be something to do with either changing mod settings or upgrading. To fix it, run this command (paste it into the console):

/c 
for _, force in pairs(game.forces) do
  for tech_name, tech in pairs(force.technologies) do
    if tech.enabled == false then
      if game.technology_prototypes[tech_name].enabled == true then
        game.player.print("Enabled tech: [technology="..tech_name.."]")
        tech.enabled = true
      end
    end
  end
end

Thank you :)