A lot of breakpoints but this will depend on if you have a v6 Klukai or not, as I think you should only heavily invest into her after v6 Klukai.
Any dupes not mentioned provide too little of a damage upgrade to mention.
Her v1 is great like all the other units before her, raising the limit on sugar stacks for a higher damage ceiling. V3 gives you sugar trap every turn for even more debuffs and even more damage.
V6 gives her the ability to use ult every turn after she has done ramping up sugar and also allows her to trigger v6 Klukai's dot twice every turn, making her a self sustaining unit that doesn't really need other corrosion units, but it's still nice to include a Mechty for the synergy with her key or a v6 Klukai.
For weapons there's 3 options, one is her signature, second is Sabrina's weapon at max dupes and the third is the battle pass shotgun at high dupes. If you have the bp and you already have enough ARs, get the bp shotgun. If you're an f2p, just use sabrina's weapon.