I don't think these are generally comparable situations. The geography of the Narva Isthmus constrained the scope of the operation (by the standards of the Eastern Front), while Operation Bagration was truly a massive undertaking.

At Narva, the isthmus is only about forty miles wide; that's not bad frontage for a field army sized force, and the river Narva worked as a barrier and a funnel, where Soviet forces were concentrated at their bridgeheads, further limiting the frontage and evening the odds between the Germans and Soviets. The Germans had selected this portion of the front as highly defensible, so they constructed their 'Panther' defensive line here, with the 'Wotan' line on the other side of Lape Peipus stretching to the Black Sea. The Germans usually had mobile forces available for counterattacks against Soviet formations, so the Soviets weren't able to build up a decisive superiority for a breakthrough or get inside the Germans' decision making loop. The main effort at this time as being made in Ukraine far to the south, so the Narva offensive was of secondary importance.

By contrast, Operation Bagration had been marked as a key offensive for summer 1944. There were four Fronts (1st Baltic, 1st-3rd Belorussian) involved on the soviet side, with another Front (1st Ukrainian) performing a mutually supporting operation immediately do the south. In contrast to the Narva offensive, with its constrained area of operations and relative parity of forces, the Soviets were able to play to their strengths much better in Belarus. German defenses were thinly stretched in a gigantic salient. German defensive doctrine called for phased withdrawals through multiple lines of prepared defenses, followed by swift counterattacks. This was impossible in a sector where a division with six infantry battalions had to defend thirty two kilometers; rather than defense in depth, the Germans had only isolated listening posts and patrols stringing the widely separated battalions at the front together. Much of Army Group Center was occupied with anti-partisan operations in the rear; Estonians had only recently been conquered by the Soviets prior to the war, and the Germans got valuable support from them, while Belarus was a longtime Soviet republic, had been horribly brutalized during the invasion, and its vast marshes provided shelter for partisans, who intensified their operations in preparations for the offensive.

Stretching the Germans even further, the Soviets conducted good deception-concealment campaigns; Konev's 1st Ukrainian Front did not hide its buildup of strength, and the Germans believed the Soviets would strike at their allies in the north and south. The Romanians seemed to be wavering after heavy casualties during the retreat from the Dnepr river. Moreover, the Finns had not fought vigorously for much of the war, hedging their bets, but were now being subjected to great Soviet pressure, which could force them out of the Axis camp. Believing 1st Ukrainian's buildup to be a sign they intended to strike south towards the Romanians, the Germans transferred LVI Panzer Corps from Army Group Center to Army Group North Ukraine, where they hoped to use them to cut off a Soviet southward advance. The only reserve AGC had was 20th Panzer division, and it was under the control of the Army High Command (OKH) rather than the army group.

Meanwhile, the Soviets managed to keep their buildup against AGC under wraps; while the Germans had a fairly accurate picture of what the Soviets had right in front of them, OKH intelligence for the Eastern Front (Foreign Armies East) completely missed the transfer of three armies, one tank army, and multiple mobile corps to sectors opposite AGC. There were a couple reasons for this. The Soviets had become very good at enforcing iron radio discipline; German signals intelligence didn't have much to work with. German air recon was also limited, as the Eastern Front had lost priority to defense against the Western Allies' strategic bombing, as well as tactical commitments against the AEF in Normandy. Furthermore, as you alluded on that note, the Germans committed a lot of their best tank units to the reopened western front, so when the Soviets smashed the infantry at the front, the Germans had no way to respond.

When the Soviets launched their attacks, they took a few measures which helped secure its success. The initial attack was performed in echelon, from north to south, and by recon battalions detached from their parent divisions. This method became known as 'developing reconnaissance into battle', and 1st Baltic Front carried it out on a broad front; to the Germans, this scattered light attack just seemed like a demonstration, not the harbinger of the main offensive, so rather than withdrawing, they counterattacked, sticking to their forward positions. This reconnaissance in force also ensured that their artillery would not fall on empty trenches. The main assault began on June 23rd, and quickly crashed through the brittle German line; by June 25th, 1st Baltic and 3rd Belorussian fronts had encircled four German divisions of LIII Corps at Vitebsk, and there were no reserves to rescue them. With the way open, Eleventh Guards Army in 1st Baltic could rapidly drive to Minsk, where it linked up with Sixty Fifth Army from 1st Belorussian, which had already encircled an entire German army in its forward positions on the southern face of the salient.

Operation Bagration was successful because the General Staff developed the skills and built up the materiel to find the ideal area for operations, to stretch the Germans to the breaking point, to mass their forces in secret, and to make skillful, violent attacks, followed up with rapid exploitation. I'm inclined to view the stalemate at Narva as something of a fluke, insofar as every operation isn't a fluke; the Germans were fighting in relatively constrained, fortified positions, where their declining mobility and inferiority in numbers were less important than in the vast spaces of Belarus, Poland, and Ukraine.

Check out

The Road to Berlin by John Erickson

When Titans Clashed by David Glantz

Both provide a good overview for the preparations for Bagration. Glantz and Orenstein have also translated Soviet General Staff studies of the Belorussian and Lvov campaigns, though I don't know of a book length treatment of the 1944 campaign in the north.