Apart from all the other matters that I cannot honestly comment on due to lack of knowledge, what do you mean about the ruin of the army and diplomacy? From where I'm sitting and from the information I have, it's a bit inconsistent and debatable. The Polish army began to modernize under the Law and Justice party, while its predecessors destroyed it (withdrawal of units from the east, purchase of ill-fated equipment like H225M Caracal), and foreign policy saw a turn in favor of America and the countries of Central and Eastern Europe at the expense of the EU, France and Germany ( something that will probably also happen in this TLL and much earlier, looking at the last chapter).
So, on the topic of military: first off, about the Caracals, the main grievance was, from what I have heard, that Macierewicz breaking off the deal resulted in costing Poland a lot more money, and getting new helicopters much later and fewer than if we had just continued on with the deal. I'm not a military expert, so I have to admit I don't know how good they actually are. Secondly, in probably one of the more infamous moments of his tenure as Defence Minister he ordered what was essentially a break-in into a NATO counterintelligence center in Warsaw back in 2016, hurting the trust between Polish gov't and NATO. IIRC he also released the names of at least some of our military intelligence agents, which obviously had a very damaging effect on what used to be one of the best intelligence forces in Eastern Europe. Also there are accusations of him being tied to Russian interests, but I will not make a comment on those as I am underinformed about them (I mean, I believe them, but it's not a hill I want to defend).
Błaszczak was better, there at least no accusations of being a Russian asset made against him, and army modernization did pick up under him, but he was not free from the general corruption that slowed it down. And, because I can't be seen giving him too much praise, I have to mention the incident when in late 2022 Russia sent a dummy missile (i.e. one with no explosive charge) that landed near Bydgoszcz, and the government failed to inform anyone about it, and they failed to find the missile too until months later it was randomly found by a civilian. So, in summary, while perhaps total ruination was a hyperbolic statement on my part, I stand by the opinion that it was not a good time for our military until around 2022.
As for diplomacy: It was not a pivot towards America, it was a pivot towards the Trump administration. When Biden won our relations with America markedly worsened (did you know it took weeks for our President to actually congratulate Biden on his victory? And that after the Trump-appointed ambassador to Warsaw left, we wouldn't approve a replacement until February 2022?), and to this day Law and Justice is very much more friendly with the GOP than the Dems, when the previous governments got along with DC just fine regardless of if the White House or Congress was red or blue. What you call a turn in favor of East and Central Europe at the expense of EU I call burning bridges, but more importantly major figures from the party, including Prime Minister Morawiecki, met with openly pro-Russian politicians like Marine Le Pen, Matteo Salvini, Santiago Abascal, and Viktor Orbán as late as December 2021 when our gov't had already received American intel that Russia was going to invade Ukraine. Fundamentally, that government did not care about diplomacy, and all actions taken on the foreign front were performative, meant to shore up domestic support. We can have a fruitful discussion about the merits of the diplomatic pivot you have described, but fundamentally that's not what Law and Justice did. What they did was buddy up to fellow Putinists in hopes of building a block that will defend them from EU scrutiny and excite their base. And now we have finally returned to a diplomatic policy that is interested in doing actual diplomacy, rather than securing the interests of one party.
At least I can console myself with the idea that the changes in TTL are so far gone, Lech Kaczyński's disastrous flight to Smolensk will not happen. At least he had a conscience, unlike his twin brother, so maybe in TTL he will temper Jarosław's worst instincts. I hope.