Heretical Fishing 2 runs into the same problem all isekai genre books hit eventually. The MC is too powerful to encounter any chance of failing. He was already instantly successful at anything he tried in the first book, but at least there was some amount of training period. The only hardship he encounters this time is emotional stuff.
To counter this the author falls into the same trap to induce tension, namely, introducing a whole host of new characters. There's too many. Several are introduced, have their own little drama (typically ending in the MC solving all of their problems), then are discarded for the rest of the book.
There's a chef introduced, and the only thing he does is cry tears of joy at the MC's cooking. I get that it's too illustrate how talented the MC has become at cooking. But after the third time it happens, it loses all impact. It doesn't describe him eating other food, or cooking his own food, or really anything to showcase his culinary capacity. He brings a dish once. Other than that, his only accolades are the other characters *saying* he's a good chef.
The MC's narration is constantly reminding the reader his body has super-durability or super-reflexes or super-strength. Rather than let an event play out, there is a constant stream of interruptions to say how overpowered the MC has become.
There's also a very abrupt jump in time. Throughout the first book time passes fairly slowly, something's happening ever day and there's a constant documentation. That's less the case in this book, but still more or less true. Then suddenly there's a month gap. Of essentially 'a month went by and nothing happened'. Considering the breakneck speeds at which characters grow and their surroundings develop, the sudden month passing was jarring. And really only served the purpose of having a month pass.
Even the parts where there are fishing are of no consequence anymore. He's become too powerful to fail to catch a fish.
If Book One is a cozy slow-life japanese isekai, then Book Two has transitioned into a chinese qi cultivation manhwa. The 'getting superpowers and unlocking the secrets of the universe by sitting and meditating' kind of reading.