I’m playing a Rogue using the 2024 D&D rules. In a recent session, my character was Poisoned, so I had Disadvantage on attack rolls.

On my turn, I used Steady Aim (and sometimes the target was also Vexed), which granted me Advantage. That canceled out the Disadvantage, resulting in a normal d20 roll.

I also had an ally within 5 feet of the target, fulfilling the Sneak Attack condition—as long as I don’t have Disadvantage.

However, my DM ruled that Sneak Attack was still disqualified because I “had Disadvantage,” even though it was canceled out. The reasoning was that the Disadvantage condition still existed—even if nullified by Advantage.

My understanding:

• If Advantage and Disadvantage cancel, the roll is normal, and I no longer “have Disadvantage.”

• So, Sneak Attack should still apply if I meet the ally adjacency condition, even without Advantage.

Personally, I disagree with this (as a DM myself), but this is not my table so I did NOT argue the point. 

What I'd like as input is, is this correct by RAW (Rules as Written) in the 2024 ruleset?
If anyone has dev quotes, Sage Advice, or rulebook page references, I’d really appreciate it!

This is the DMs logic.

The attack has Advantage + Disadvantage (maybe multiple sources of each) which cancel out their effects but they don't cancel their "condition" (if I can call it that), because if they did, the rule of stacking wouldn't work.

Disadvantage is a term and rolling two dice and keeping the lowest is the effect of that term the effect is cancelled but not the status/condition/term

For the stacking to work, it implies that Advantage + Disadvantage still exist but their effects get cancelled thus more instances of each would be "stacking".

In an analogy example, I think of as if you have a feature that lets you regain 1 hp when taking damage, and you take 1 damage. It's not as none of them happening and you took no damage, both happened, you both healed and took damage, but their effects were cancelled out. which would allow other sources to trigger on damage/healing and in our case Sneak Attack still getting negated by Disadvantage across 5e I always thought that's the balancing point of Sneak attack. otherwise it's a free overpowered smite that costs no resources and you can do out of your turn too (and from range)

While I "understand" their viewpoint, If you are going by RAW, which he does say he does (and says Rule of Cool is for lazy DMs who don't know the rules), this isn't RAW. This is justifiying a NERF to Sneak Attack. It's his table, so I roll with how he runs it. Just wanted other eyeballs and input.