Re: Yes yes yes!
ZFS offers a userland tool to access the low-level parts of your block devices, vdevs, and pools: zdb. It does not hide anything from you and allows you to see all features, fields, and structures of your pools. ZFS isn't "magic", and is actually very well structured, with its use of feature flags and vendor extensions being clearly deliniated both in source code and in practice, as zdb will show you. Its simplicity might seem untrustworthy, but in reality it is actually that straightforward. Furthermore, the userland tools you are provided with are about as "manual" as you can get without redesigning the wheel—really, you could make the same claim about Btrfs, or any other monolithic, all-encompassing filesystem.
...Of course, no matter how ultimiately trivial ZFS's various systems are once you understand them, there is a good bit of jargon when you dig past the usual basic use-cases, with a lot of additional features, extensions, and configuration tweaks whose purpose and use may not be immediately apparent. There is no shying away from the fact that ZFS, being a well-matured project with lots of different tools under its belt, has a degree of complexity, but you also don't have to use or even enable the features you don't want to use on your pool. It is additionally possible to decypher ZFS internals if you have some lower-level knowledge in other filesystems, and the ZFS official documentation (both for end-users and developers) is very thorough. There are also lots of blog posts where even the practically ancient ones give lots of useful insight. Since a lot of people use it, including large corporations, there is no shortage of experts either, of which you might be able to pick the respective brains of if you ever see the chance arrive.
As an example, while the task seemed daunting at first, I managed to recover data from a completely dusted pool (a problem caused by my own negligence, no fault of ZFS—in fact if I were using it more effectively, I would have had proper redundancy that could have rebuilt the pool) by manually accessing the device with zdb. It is a very useful tool and gives you a curated, structured, parseable view of your data in a way that I have never seen from any other filesystem, and while the ease of something like extundelete would certainly be welcomed if anyone would want to make something like that, I ultimately had everything I needed to play part-time data analyst and recover what I needed without too much hassle.
I used this article at the time to get my bearings with zdb. It should still be relevant. Haven't had the need to look anything up since due to a lack of problems, now that I know what I'm doing.