stock automatic weapons are generally useful at close ranges or on single fire, but fully shine with accurate bursts at medium range but most guns really benefit in this department from modding, which can get expensive.
which brings me to an important point: beginners are best served with accurate semi-auto weapons. the sks, any shotgun or any of the veprs (hunter, 136, 209, 215) teach you accurate shooting and good positioning which is more important in tarkov over spraying at the target.
the sks has long been touted as the rookie king gun because it fires good ammo thats still affordable and the gun works well with no to minimal modding, firing accurately at ranges and you can fire it almost as fast as you can click for quick panic fire if someone ambushes you at close range.
shotguns with long barrels fire narrow cones of shot that can easily hit someones face even at medium ranges and put them down in one shot, especially scavs, and buckshot is generally cheap.
the vepr hunter fires strong ammo accurately and is semi auto making it the sks's badder older brother. the 136 is just a semi auto AK and the 209 fires unique weird ammo and is also basically a semi auto AK. both of these are cheap guns and are highly moddable for cheap builds that can be translated to actual auto AKs. the 215 is a cheap bolt action that fires the same round as the 209, making it a serviceable sniper with a cheap scope.
other than the vepr hunter, these guns also have a very high chance of coming back in insurances unless they've been heavily modded and even then the sights, silencer and/or laser pointers/flashlights will just be stripped off and you'll get the gun back.