I have a bit of a hot take: Off-Turn Sneak Attack is mechanically not something I like
Part of a major criticism I have with Rogue is that the design space for the class is largely and heavily limited, and I find that enabling off-turn Sneak Attack contributed a bit too heavily to their overall power budget that no other meaningful changes could've been made to the class in the 2024 edition.
On Fighters, people wanted Maneuvers to be class-wide. As a semi-close concession, we got Tactical Shift, Tactical Mind, and Tactical Master, which the former two use up resources the class already had while Tactical Master is a genuinely free feature that doesn't take up any of the power budget the class gained in 2024. It is now probably the best Martial in the game's overall design space and has fully fulfilled its class power fantasy in a way that doesn't completely overshadow the ideas of other classes.
Rogues have such a tight design space and power budget because they are tasked with 2 things: Get Advantage on your Attack Roll, and apply your Skills(Expertise) well. Despite that, they only ever get 1 attack, they have the slowest class and feat progression out of any other class(they don't get their second subclass feature until the END of tier 2 and they only get 1 extra feat to show for it).
More than 50% of their power budget is tied to spending their Reaction to find a way to perform off-turn Sneak Attack using Opportunity Attacks. You can't Ready an Action and use the Attack Action on your same turn, you need to find a way to CC enemies off-turn and enable that Sneak without giving up your Advantage and without taking damage in that same turn due to using up your Uncanny Dodge.
I think a slightly better alternative would've been to allow Rogues to treat their Sneak Attack dice as something they can split up between attacks, and instead just increase the amount they get at different intervals. Maybe give them 2 every time it increases instead of just 1. That way you aren't hard-lining all your damage into a singular funnel and finagling an off-turn sneak attack that uses more of your action economy and prevents defensive utility.
A mechanical example of this would be that a 3rd Level rogue would have 3 Sneak Attack dice, and would be dual-wielding a shortsword and a dagger. They have advantage on the first attack because they were just hiding, so they get the Sneak Attack, but instead of using all 3d6, they just use 2d6. They end up killing the enemy they attack with just the 1d6+Dex from the shortsword and the 2d6 from the Sneak Attack, which then allows the Rogue to attack another target with the Nick Mastery, and let's assume they also manage to get Sneak Attack on them as well(maybe they have Skulker) and deal 1d4+1d6 to the second target instead of pumping ALL of their sneak attack into the first attack, overkilling, and then only dealing an average of 2 damage to the second foe and wasting their damage economy. And if they want to do off-turn sneak attacks, they still can, but without sacrificing design space to a niche mechanic.
I recognize that I might not necessarily be smart enough to really have a standing opinion, but the idea that Rogues were (nearly) entirely unchanged from 2014 to 2024 and their overall progression sucking as bad is it does leaves a sour taste in my mouth considering all of the UA that the community went through and ended up voting on. Part of why Martials didn't get that much better is also on the people who made the votes, and it's no longer just WoTC's design space.