Right now I'm at 354k for Path of exile currency RF and 725k for Fire Trap and I don't know what else I should improve? I'm also having a hard time farming currency (most are indicated in Delirium on the atlas and I've grown and sold cold POE orbs, POE Currency) so any advice in that respect would be good too. Just a note about gem levels - I accidentally (sort of) decided to upgrade my main RF gem from level 20 to level 1 at 20% quality, so I'm upgrading this gem in my traded gear and the main gem is still leveling up (currently at level 18) so I know my DPS for RF will increase a bit more once it hits level 20. Hoping to transfer 20% quality mine to vaal RF 21/20 and sell for god 11 but yes I have about 1.3 currency divs now.

So I didn't play RF Juggernaut until late game. But I played RF Inquisitor.

A few things to consider in terms of upgrades. Helmet: pretty decent. I guess that's where your Firetrap plugs in. But you can make or buy a better one with focus effect, elemental damage, burn damage. If you get a good bar, some players swap their RF into the stick and throw a Firetrap 6L, to help with single-target DPS.

Armor: Basic/ES running armor is pretty wasteful for Juggernaut (great for Inquisitors). Upgrading to POE currency buy pure armor or brass dome will greatly increase your armor via Juggernaut's ancestor button and with Brass Dome you will get maximum resistance and reduced critical hit.