4x5 is not the "biggest gun". It is a very standard-sized and common enlarger; perhaps more so than medium format enlargers. I would say "industry standard". When someone says "enlarger", a 4x5 enlarger is what comes to mind. When someone talks about a "big gun", a Durst or DeVere comes to mind, and/or a 5x7 or 8x10 enlarger.
No one is saying to go buy a Durst or Devere, or that the OP has to get a 4x5 enlarger; just mentioning that 4x5s are more versatile for not much more money.
This being said, I do not have one at this point, because I have a 6x6 enlarger that was given to me, and I have not actually sought out a larger one for my current home darkroom. If I was to actually seek one out however, I would seek out a 4x5 enlarger, even though I mostly print 35mm to 6x9. I just view them as a good "standard" enlarger, especially with the minimal used-market price differences between them and medium-format-only enlargers.