https://forum.warthunder.com/t/disable-cas-from-5-0-8-0/96789/57
SPAA before radar SPAA are not capable of intercepting CAS.
Once Radar SPAA are made available CAS begins to gain CCIP and CCRP for bombs allowing them to completely outrange said SPAA, this also ignores helicopters who have a range of ~3KM while most SPAA struggle to even get a radar lock past 2KM. You can LRF the helicopter, but it can easily respond to your attempts to long range fire as tracers are very bright.
The only BRs where SPAA is “preventative” is 10.3+, but at these BRs CAS is given guided munitions some FNF. Missile travel time means they can have fired on your position before your missile is halfway to them, giving them ample time to evade. This also ignores that at these BRs the only two SACLOS SPAAs capable of outranging SPAA’s guided munition range are the ITO90M and the Pantsir. Even that ignores that Gaijin has decided to add in 40KM range Laser Guided missiles in the most recent update which outrange every SPAA found ingame minus the Pantsir which is isolated to a single nation.
SPAA doesn’t counter CAS. Other planes do. The ability to spawn an interceptor at the start of a match is the only way CAS can be considered “countered”.