in obtain diamonds it is much quicker to complete with the old hub which we obviously cant use anymore, make a new catogery for obtaining diamonds on the NEW hub to make this shit fair

The old hub was slightly faster by maybe 2 to 3 seconds. However, since the dwarven mines update updated mining tech, the whole mining section is now faster by a minute or more. So the fastest combination would have been old hub + fast mining tech (which never existed at the same time) and the next fastest would be new hub + fast mining tech, which is how the game is today.

TLDR: New hub is faster because of new mining tech added after new hub update

Yeah new hub isn't faster, mining speed is just way faster now.

Also making categories for old hub and new hub would be pointless since you can't even run on the old hub.