How did Red Army achieve to manipulate German Army in 1942 and 1943?

In military science there is an important concept of “logistics.” This encompasses the strategic and operational capacity to ensure continued communications, supply, replacements, reinforcements and a line of retreat. Logistics is very linear: railways, rivers, road networks, ports, air ports and bridges are all linear. When these lines are retarded by partisans, threatened or cut the dependent forces will become less effective or (if unable to retreat) destroyed or surrender. Maintaining these lines of supply and communication are vital.

A failed secondary operation may successfully threaten a line it does not cut. “One more push” could cut the line, and the forces dependent may not be worth the risk.

Secondarily, a secondary offensive may lengthen or produce indefensible salients in a front. The defender, if able, would benefit from straightening the front by retreat and reducing the attackers ability to concentrate forces.

Don't take German sources at face value

While it is often said “History is written by the victors", in case of WW2 Eastern Front, for the Western audience history was written mostly by loosing side. Reasons for this are relatively simple, with the advent of Cold War and Iron Curtain former Soviet allies became enemies, and many of the former German officers (including generals) were now new NATO allies. Exploits of Wehrmacht (and to a lesser extent Waffen SS) against "Soviet horde" become useful example for prospective new world war. Therefore, memories and other documents coming from German side were often uncritically accepted as gospel. On the other hand, Soviet historiography was either unknown, or dismissed as crude propaganda. Truth however is somewhat different. While Soviets did engage in propaganda, and glossed over their worst defeats and blunders, Germans too were often lying and distorting the truth about their casualties, size of the enemy and damage inflicted. Only recently, with cross checking of data from both size, some glimpses of truth could be found. Now for your examples :

• In late 1942, Soviets did encircle German 6th Army and parts of the 4th Panzer Army in Operation Uranus. Germans did launch relief effort Operation Winter Storm. You will not that Russian sources about this operation differ greatly from German ones. For example, Germans claim they attacked with 50 000 men and 250 tanks vs Soviet 150 000 men and 630 tanks. Soviets claim that Germans attacked with 124 000 man and 650 tanks against 115 000 man and 329 Soviet tanks. Anyway, relief effort ultimately failed, and subsequent Soviet offensive Operation Little Saturn practically wiped out remaining German allies and doomed German troops in Stalingrad. Soviet casualties were probably higher then German, but nowhere near 6:1 ratio. If you count in Romanians, Italians and Hungarians, Axis losses were actually substantially higher then Soviet ones.

• In 1943 Kursk battles, Germans certainly did not destroy "thousands" of Soviet tanks there, unless you count in subsequent Soviet offensive operations like Operation Kutuzov and Operation Polkovodets Rumyantsev. If you count that in, German losses become great themselves, even if their "creative" accounting techniques were they numbered many AFV as repairable only to write them off later. These Soviet attacks were bloody and costly, but certainly not unsuccessful. There is one Soviet attack that Germans did repulse and that is first Mius offensive, but consequently they were forced to yield ground in second Mius offensive month latter. Overall, Germany lost initiative in the summer of 1943 and was constantly in retreat all the way to Berlin in 1945.

• As for Germans breaking third and last Soviet line of defense during Kursk (near Prokhorovka) that is also a falsehood. As the map shows, Leibstandarte Adolf Hitler was at the tip of penetration, few kilometers from Prokhorovka on July 11, but they had 9th Guards Airborne division ahead of them in fortified position. These were tough airborne troops, much better trained and with higher morale then usual Soviet infantry. Despite heavy casualties, Soviets did hit hard LSSAH on July 12, and trough memories of Waffen SS officers like Rudolf von Ribbentrop you could see that Soviet tanks did get close to German tanks and half-tracks, even forcing Germans to ram tanks with latter. Consequently, Germans never took Prokhorovka station, as after July 12 it was reinforced with remaining troops of 5th Guards Tank Army. After Prokhorovka Germans did try some local offensives like Operation Roland somewhat westwards of Prokhorovka, but because of aforementioned deteriorating situation elsewhere (Mius,Orel, landings in Sicily ...) they had to redeploy their armored forces to other places.

Overall assessment of the situation would be that German to Soviet casualty ratio in late 1942 and 1943 is somewhere near 1:2, both for men and AFV . In some places Germans did achieve better casualty ratio, but in some places they actually lost more troops then Soviets did. Both sides tend to skip "bad examples" and emphasize only victories.