Inconsistent photo syncing from MacBook to iPad via USB-C

tl;dr - I have some photos that will only sync to my iPad if I also sync the Media type albums over. When I do, those photos only appear in those albums, regardless of how they're sorted on my Macbook. How do I sync over my complete albums?

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I want to put all of my photo albums that I made in Photos on my Mac onto my iPad via a USB-C cable (I don't use iCloud for photos for grumpy old man reasons). In total, this is approximately 7,400 photos and like 30 albums or something.

• The iPad is a iPad Air 5th Gen. running 18.5
• My Mac is a 2020 M1 running Sequoia 15.5
• I have about 200GB free space on the iPad (more than enough for my photos)

I plugged my iPad into my Macbook using a USB-C cable. I enabled photo syncing in the Finder, then selected the albums I wanted carried over (which was all of the ones I made and not the system generated ones like Media type because I don't want albums full of just my selfies).

But some photos aren't in the albums they're supposed to be in, and others aren't getting transferred into my iPad library at all. For example, I have an album on my computer that's 176 photos but only 131 are on my iPad album. What's weirder is that it fluctuates occasionally; that same album was at 135 photos last week, but dropped to 131 while troubleshooting. There's no method to the madness as to which ones it decides to not move. In total, I can get about 6,500 photos on my iPad at once (out of 7,400).

When I first got this iPad, I had similar troubles syncing my books over. I eventually caved and just synced via iCloud, but my iPad regularly deletes the books I've added via Finder. It's infuriating, but not the main problem (though maybe a pattern?).

I also recently got a new phone (16e), and noticed that some photos weren't transferring to it, either. Whether it happened before I got the new phone or not, I don't recall.

So far, to no avail, I have tried to solve this problem by:

• removing all of the photo albums from the iPad, restarting the iPad and my computer, then re-uploading an album to the iPad
• doing that step again, but repairing my photo library on Mac
• checking the settings for anything anomalous along with the Apple Support technician via screensharing
• trying a new cord to connect to my computer
• reinstalling Sequoia on my computer
• resetting the iPad back to factory settings and not recovering via a backup (set up as new)

The only thing I've done that's made an impact was: at the guidance of an Apple Support person, I created a new login on my computer with admin permissions, and 'synced' my iPad to clear out the old photos, then logged back into my main one. While re-adding my albums, I mindlessly selected "Sync all photos and albums" instead of selecting the albums I wanted. After which, the Finder said it was moving all 7,400 photos over.

This is where I discovered that while all of the photos were transferred over, a lot of the previously missing photos were only in the Media Type albums ("Selfies", "Portraits", etc) but still weren't in the albums that they were in on my Macbook.

Called Support again who first tried to tell me that it'd just be easier to use iCloud (which I declined), but after a hour of troubleshooting, they recommended I reinstall Sequoia on my computer. I've done that and when it didn't work, I reset the iPad to give both a 'clean slate', but no dice. I can still only get 135 or 135 out of 176 photos in the album I keep testing.

Does anyone here have tips for what to do next? I can't even tell if this is an iPad problem or one with my Macbook.

[Re-Titled by Moderator]

Original Title:  Some (not all) photos not syncing via Finder (Macbook to iPad via USB-C)