I would like some official explanations regarding the Switch

While official explanations would be nice, it is possible there could be business deals that make it difficult for anyone to comment on these things in detail. Since the port was outsourced to my understanding, it can be hard to say who is to blame. The different parties might not want to get involved into a finger pointing contest.

I don't think they're referring just to the 30 fps - they say the frame rate is inconsistent,  that the input is laggy (which could partly be due to the frame rate), that loading is excessive, and that the game does crash sometimes.

The mere fact that they believe they can release patches to improve performance on a per-area basis means they know that the optimization process was most decidedly not finished when the game released.

I don't believe there will be an official explanation beyond what they've already said (basically, that they're sorry and will be improving the game through patches).

Anyway, I've often defended the devs and the publisher, but the game was clearly released before optimization, debugging and overall quality assurance were done.

I mean, the PC version runs perfectly, except for loot bags getting stuck in the environment literally half the time (a big deal, if you ask me), and the game crashing every 4 or 5 hours (a pretty big deal, too). That the best version of the game has evident bugs that can be discovered through a simple playthrough, without the player looking to break the game, tells you all you need to know about how good the QA process went.

Now, whether the game launching in this state was due to miscommunication, naivete, incompetence, negligence, or management at the publisher demanding a release date and making everyone stick to it regardless of how polished the game was is something we might never know.

What can be said is that this is ultimately the publisher's fault, because it's 505's job to be on top of these things, to identify issues with the build they are sent and make decisions based on those builds.

And they squandered a lot of the goodwill and praised the game earned by releasing the Switch version in an unsatisfactory state - which is a shame.

They need a post-mortem on this, and a good one.

I sure hope so, because I really want this game to succeed and to become a franchise.

For the reputation of the quickly responding to criticism and being determined to support their fans to stick, they need to avoid these mistakes in the future.

Remember when there was a time some of you (not me, though) honestly thought they could pull off a WiiU and Vita ports of this game? Remember that? Because I'm glad they canceled those, though.