Basically I got 3 SRH before getting HKoF or Nepthys. I'm kind of regretting it so is it worth it to go again?
Depends on the deck you want to build; it's a decent multi-use anti meta card, but you have to be the one to determine if the investment is worth it
Maybe you should, balance board control is platinum climber and maybe legend too, but nobody knows
Depends on what kind of deck you'd like to build. 3 SRH are useful in any situation. HKoF or Nephtys... not so much and you'd be committing to a particular deck image. You want to play with HKoF or Nephthys? Then go again! If you'd rather build another archetype (Umi, REBD, Ritual, Dark Magic, etc.) choose one thing and focus in on it. SRH will be a powerful addition no matter what you do.