Have you tried Phantom Phoenix? I've found it to outperform just about everything, and it's pre-Plantera.The truth is that I was in the middle of a Ranger playthrough (since v1.4.4, I was playing with every Class), and I still had the assumption that Bows and Repeaters could compete with Guns Pre-Plantera.
Even when stacking all three Magic Quivers and using Cursed Arrows, not even the Titanium Repeater could compete with something like the Onyx Blaster with Crystal Bullets. I should have tested Holy Arrows, and I will.
Yeah, I also saw that stacking Cursed Flames + Frostbite + (not yet) Hellfire as Ranger wouldn't be as strong as I was thinking.
At this point I'm thinking about a rework to the Magic Quivers themselves, because all Pre-Plantera Bows and Repeaters are inferior to Guns (not counting Daedalus Stormbow and, obviously, Tsunami); maybe they could give them the same increased-over-time fire rate mechanic as the Phantasm, without stacking it while using the variants. This maybe would need to remove the +10% increased Arrow Damage on the three Accessories. (Along with the proposed Hellfire buff to the Molten Quiver, maybe the Stalker's Quiver could still have the Putrid Scent's +5% bonuses but only applied to Arrow Damage and Arrow Critical Strike Chance.)