The transition from First to Second Corinthians is not as seamless as one may assume. Yes, it's the same congregation and the same author but readers of both books will note dissimilarities, even in the ease of reading and understanding. As one commentator notes:
Few portions of the New Testament pose as many problems for translators and interpreters as does 2 Corinthians. Few, therefore, are the preachers who undertake a systematic exposition of its contents. For those undaunted by its demands, however, an intimate picture of a pastor’s heart may be found as the Apostle Paul shepherded the wayward Corinthians and revealed a love which comes only from God (David K. Lowery, “2 Corinthians,” The Bible Knowledge Commentary, 550–551).
We should consider the grasping of "an intimate picture of a pastor's heart," particularly one that so beautifully mirrors the Saviour's heart for his people, worth the effort of study—even study of a difficult text.
Thankfully, we have a capable mind leading us in this endeavour today: Dr. Ed Glasscock. Dr. Glasscock has spent decades pastoring churches, teaching theology, mentoring Christians, and writing books and articles. He's also a pastor and a pastor of pastors, so he knows well, is inspired by, and is constantly himself pursuing the pastoral heart on display in Paul's second letter to the church in Corinth.