How long does it take to collect all the spiderweb anomalies on an alt account?

How long would it take to get enough currency to buy all the spider-themed characters if I grind the spider dungeon non-stop?

Since the hard dungeon isn't open, I don't think anyone will be able to get the full price before the season changes...

If there are many characters you want to pull, you should skip this season and save up for the next one. The characters next season are expected to be better anyway.