(NB: I originally wrote this for another forum but I figured the information was worth posting here too for educational purposes).
People keep asking what Russian air defences are doing, like they have ever done anything. Here is a verbose list of all the major successes of Russian/Soviet air defences in the past 25 years:
27 March 1999: Serbian forces hit the jackpot and the stars align for them to score a billion to one shoot down on an F-117 with an S-125
4 October 2001: Ukrainian forces accidentally shoot down an airliner with an S-200 after it misses it's target drone during an exercise then fails to self destruct
9 August 2008: Georgian forces shoot down a Russian Tu-22MR reconnaissance aircraft with a Buk
14 July 2014: Russian forces in eastern Ukraine shoot down a Ukrainian transport plane with a Buk
17 July 2014: Russian forces in eastern Ukraine accidentally shoot down an airliner with a Buk
8 January 2020: Iranian forces accidentally shoot down an airliner with a Tor
18 July 2022: Russian forces accidentally shoot down their own Su-34 with an undisclosed SAM
23 August 2023: Russian forces shoot down Wagner's airliner with an undisclosed SAM
15 Jan 2024: Ukraine shoot down an A-50 with an undisclosed SAM (potentially an S-200)
As you can see, there's only 9 of them, one of which was a fluke, one of which is still unconfirmed if it was a Russia/Soviet missile, and four of which were airliners with zero defensive measures or even a warning system to tell them to take evasive action. The only thing on the list that couldn't have been stopped by a missile from the 1950s (excluding the F-117 that was stopped by a missile from the 1950s due to a fluke) was their own Su-34!
Every single time Soviet/Russian air defence missiles have been used against anything worth defending against they have completely failed to do their job. They failed to protect Iraq from Israel, they failed to protect Iraq from the US led coalition, they failed to protect Serbia from NATO (scoring a billion to one hit on an F-117 does not make up for doing nothing against the 1000s of other bombing sorties flown), they failed to protect Iraq from another US led coalition, they failed to protect Libya from a French led coalition and they failed to protect Syria from a US led coalition. The only time they have ever actually performed above terrible was in the defence of Ukraine, because Ukraine spent eight years upgrading/modernising them to not suck.
So in answer to the previous question of what the Russia air defence is doing, the answer is sucking (as usual).