I also have a very hands-on approach, which is why I chose iTunes. I wouldn't say that it "automates" my processes- it's just a database interface in lieu of the file system. It gives me very granular control without having to work at the file system level, and ends up reducing errors and facilitating curation.
I can see how splitting your library saves local disk space. It would make me a little nervous, though.
Why would it make you nervous? I suppose using a cloud service could always mean you lose everything but people on here are forever saying that yet another hard drive has failed.

Also, I've recently been digitising hundreds of DVDRs (that I used as an archive & back up, as well as a library of things I'd recorded off the telly) & a lot of those are problematic, so that turns out not to have been a 100% successful storage medium, either!
Dropbox (& I assume it's the same as any other similar service) allows me to right click & bring any album down to my desktop so that I can edit it & then send it back up into the cloud. It's a seamless system & I love it! I have a Dropbox Business account, so I have unlimited space (currently at 16 terabytes, I gather) for all my movies, music, work, photos. The whole shebang.
As far as granular control is concerned, I really do like to go in at a system level. I like everything in my iTunes & on my hard drive to match. All the album titles are the same wherever I look at them & I really like that.
Why don't you use Apple lossless instead of AIFF?
AIFF has always been the native format that CDs rip to on a Mac so I've just stuck with it. I don't know about Apple Lossless but I'm loath to use any Apple specific file formats in general. I've always used Apple computers at home & at work, so I'm very comfortable in that ecosystem, in fact, I love it for many, many reasons, but I steer clear of all the things they do to make life simple for people who don't feel the need to be in control. I believe that most of these things are for Apple's benefit, rather than the user. They
want you to use Apple Music & TV & they want to be in control of everything you consume so that strive to make it easier for that to happen.
It makes sense as a business strategy but personally, I do need to be in control & I use a lot of third party apps that meet my needs.
They're forever tweaking & changing iTunes &, as a result, I've had to spend endless hours re-tagging things over the years. I shall avoid the temptation to ramble on about it for hours, as that really isn't the point of this thread. Suffice to say I've abandoned sort fields, etc. & have devised a way to let the Album Title & the Album Artist do all the heavy lifting. If I keep it super simple, whatever they decide to change in the background won't affect my filing system & all the key information will be where it needs to be if I go over to a different system one day.
That change kinda led me to a place where I was adding a lot of information into the album title (as you can see from the screen shot above) which I really like. I can see release dates, different versions of the same album & everything sorts the way I like it.
