Thank you for all of these details – it really helps!
That’s good, because that means you can fix everything from one place. The goal will be to get that MacBook collection looking perfect, and then use that to paper over whatever is going on in your Windows install. So all of these suggestions you should do on your MacBook.
This is obviously going to be a problem, since it’s about 20x the collection limit for syncing. 
There are a few ways to track down what is happening there, so you’ve got some sleuthing to do.
- If you go into the
backupsfolder for your profile, you’ll see those 70+ backup files that Anki has been automatically making for you. They are in order by date, so look for big size jumps and think about what happened around those dates. You mentioned something changed in the past month or so, and I bet you’ll see that there too. - Use the Note Size add-on to figure out what decks/notes in your collection have ballooned in size. [You already have a lot of add-ons, so I am reluctant to recommend another, but this has been really helpful for folks finding runaway size issues. I recommend that after you get what you need from it, you disable or remove it.]
- At the bottom of the Decks page, hover over the “Collection” size to make sure it’s not the revolgs that are the issue. [New feature added in April 2025]
- In Browse, try showing the “Size” or “Size (text)” column, and sorting by it to see what the largest notes are.
- Looking at those notes, if there’s no visible excess of text, check the HTML view of the fields by clicking the
< >above the field. Text can be hiding in your fields from things you copied in from other locations that brought too much formatting with them. [A favorite I keep seeing in my own collection is pointless HTML formatting applied to every word/punctuation char, like coding"much":as –
<span style="font-weight: inherit; font-style: inherit;">"much</span>
<span style="font-weight: inherit; font-style: inherit;">"</span>
<span style="font-weight: inherit; font-style: inherit;">: </span>
When you find the troublemakers, start with the simple things:
- Delete all notes/decks you don’t need. [And when you do, run Check Media and delete unused media again.]
- Run Tools > Check Database and make sure you don’t have issues there.
- If you see patterns of useless text (like the “inherit” one above), you should be able to Find & Replace them away.
Looking at the size of your collection, I doubt that is going to be enough, but it will help focus your attention on what else is needed.
Given the ballooning size and slowness issues you’re having –
- Consider starting Anki in “safe mode” to disable all of your add-ons at once.
- If you database is struggling, you may need to think about exporting your collection data and starting fresh in another profile by importing that in.
It’s quite comforting that your collections have the same number of missing files. Hopefully that number will go down as you start deleting unnecessary/incomplete decks. It’s also okay to run Check Media again to delete the media trash folder.