After your revision, the sniper rifle D.A.R.C.I. mutated into a true DPS monster and practically the strongest weapon in Destiny 2. However, with the recently added Whisper of the Worm, there is now serious competition. Which is the better sniper?
Which sniper rifle is currently the strongest in the game? This question has now been addressed by Reddit user dl33t3d in the context of an extensive test. The previous top favorite D.A.R.C.I. was compared with the new Whisper of the Worm – the only weapon that can really challenge the current frontrunner. The results of this test are certainly worth a closer look.
Does Whisper of the Worm dethrone D.A.R.C.I. from the DPS throne?
More than just yes or no: While one could simply say that Whisper of the Worm surpasses D.A.R.C.I. over time, this answer does not do justice to either sniper rifle. Rather, the correct answer relates to the circumstances under which either of these top snipers is the better choice.
In simplified terms: To save you from the confusing numerical mess, we summarize the test results in a clear and concise manner. Those interested in the exact details should check out the corresponding Reddit thread and the accompanying spreadsheet.

The D.A.R.C.I. fires faster than the Whisper sniper and can thus expend its ammunition supplies more quickly (with Lunafacture boots of the Warlock, so reloading is not necessary). It deals higher damage over a shorter period of time.
If a damage phase lasts less than 12.5 seconds, D.A.R.C.I.’s damage output is higher within this time frame. Only when it runs out of ammunition do the DPS numbers stall.
The Whisper of the Worm on the other hand excels when a damage phase lasts longer than 12.5 seconds. Because after this time, the new sniper surpasses the former frontrunner.
Its theoretically endless ammunition reserves contribute enormously to this. Because when the fight is over for D.A.R.C.I. due to lack of ammunition, the Whisper sniper really comes into its own. If a fight lasts three minutes, it hardly matters how much damage was dealt in the first 15 seconds if nothing further contributes to the fight and thus the total damage.

By the way: These values do not yet consider the perk Breath Control that Whisper of the Worm receives in its masterwork version. Then the Whisper of the Worm will likely outperform its direct competitor even earlier.
Which weapon is better now? Both weapons are excellent snipers and a top choice for almost any boss fight. It depends on the time window available for the respective damage phase. If you have less than 12.5 seconds, D.A.R.C.I. is the stronger alternative. If you have more time, Whisper of the Worm is currently the more powerful choice.

The masterwork variant of Whisper of the Worm will likely shift these timing figures once again in favor of the new sniper.
Note: The test values represent theoretical damage under optimal conditions. Negative influences from individual abilities, missed shots, target acquisition, handling preferences, and other disruptive factors are not taken into account in the test.
What are your experiences with these two weapons? Do you have a personal favorite?