I don't see how an attack by a thousand militants, almost certainly with light weapons, on a Russian base would be very effective.
With the helicopters there, it would be enough to neutralize them.
Depends how smart the attacking force are, but when you have a large force attacking a smaller force the problem becomes that of numbers.
If you are on your own and 10 people rushed your position... how many can you kill before they reach your position and it becomes hand to hand?
The problem is made worse when those 10 people are shooting at you so you can't just leisurely pick them off one by one... you have to take cover and move from firing position to firing position.
If they work together they could keep several firing positions under continuous fire as they approach so your chances of shooting them is reduced.
Obviously there are lots of variables... if they use vehicles you can kill them in groups, if they are on motorbikes or light dune buggy type vehicles they can be hard to hit... all coming at once is a lot of targets at once.
Plus of course they could have artillery support etc... like mortar teams etc etc.
Armed by Turkey they will have ATGMs and MANPADS and other equipment and also possibly drones from Ukraine.