Assmod or Masteries

I made a post a couple days ago asking for advice on my tower. I’ve stuck around the 450-500 wave range in Legends tournaments.

I was told to buy Core and Armor assmods to help and was also told to buy all different types of masteries (Demon Mode, Energy Net, etc)

Currently, I have 3 damage masteries:

Damage (maxed)
Super Tower (being researched to level 4)
Berserker (being researched to level 4, both will be maxed out ASAP.)

I’d appreciate a clear cut answer with an explanation which to choose please!!