Russia is busy improving its radar coverage of its own airspace and the airspace around it... the AWACS it does have help fill gaps and also support operations... an AWACS is not just a radar... if it was just a radar like a Ka-31 then it is technically called and AEW or airborne early warning aircraft... AWACS includes command and control which includes communications... in other words it doens't just look for low flying targets... it looks for all flying and ground based targets and passes that information to aircraft and ground forces... it effectively manages the air battle by assigning targets to groups of friendly aircraft providing them with target information so they don't have to use their own radar and give away their positions or presence. The AWACS manages engagements and ensures the defence and attack succeeds.
The west will talk about ground controlled Soviet and Russian air power, but the west is not really any different... they just have their ground controllers sitting in AWACS aircraft... it makes them more mobile but to certain weapons it also makes them vulnerable.
A ground controlled sitting in a van near a very large ground based radar system uses the information it provides but the ground based radar can't see low flying targets at great distances or behind hills or mountains... a controller in an AWACS can see cruise missiles from much greater distances and can see down in to valleys and behind mountain ranges etc etc
The main difference is that with Russian defences they can use AWACS to fill in any gaps in the ground radar view... the gaps are static and known so they could position some mobile radar or airship based radar to fill the gaps to save aviation fuel and get better coverage... a lot of their long wave radars bounce off the atmosphere and have no radar horizon though they can't see targets up close they can detect sea skimming targets from thousands of kms...
What Russia has that HATO does not is a fully integrated air defence network that is being unified with airforce, army, navy, and aerospace defence forces so that all their air defence capacity from fighters and bombers and SAMs and radar and optical sensors and other detection equipment including over the horizon enormous radar sets and even satellites can combine information and show what is out there so they can decide what to send against it.
Before such management you needed aircraft to patrol all the time looking for enemy incursion which burned a lot of fuel and used up lots of flight hours of aircraft and was rather inefficient... if you went too early or too late you could miss an incursion or an attack.
The current system means everything works together and can be much more efficiently and effectively used.
But Russia could go for air fight hundreds miles away over the Pacific or Arctic oceans because they will not let US aircrafts to come close to their terrorities . At distances far from air defences ,they need more AWACS .
They have over the horizon radar that cannot detect targets within 100km, but beyond 100km they can detect targets from high altitude down to sea level out to about 3,000km... so no, they don't need AWACS for that.
The Russian Army has bought some Ka-31s for battlefield management so they can see the aerial picture over the battlefield more accurately... perhaps in time when they launch a new CVN with an onboard fixed wing AWACS platform they might go for one of those to improve endurance and reduce operating costs, but knowing what is happening in a piece of airspace is valuable and worth a reasonable cost...