[Quoth]

I used the Kindle a lot for annotations. It used to be much easier to actually highlight on it than on the Kobo, Kobo fixed the text selection being slow. The only useful thing Amazon does is "Sync", which is worthless to extract from their ecosystem and pointless with only one reader.
The Kindle is poor compared to the kobo for Annotation export. You don't need ANY patches on the Kobo, or modifications. There is a line you can add to reader.conf that adds an extra menu item for a book, "Export highlights", which works. But with Calibre you don't need it and the Kobo Utilities on Calibre is far superior. There is nothing useful on Amazon's web site to get annotations (inc context) into a text editor and if there was, that's a privacy failure.

I've never gone back to using the Kindle PW3 for annotations since getting the original Kobo H2O and the Libra cost less but has a better screen.

The only advantage of the Kindle is to be able to put its serial number in a Calibre Plugin and then if I buy an Amazon book (less than 1/4 of my book spending and a fraction of my reading as read many "PD classics") then I can convert it to epub and read on the Kobo Libra.

There is no need to do anything to the Kobo. Unlike Amazon it doesn't even need a payment method or registration, a totally fake email unlocks it out of the box, though on the Kindle you can use a real email address an Amazon $1 Gift voucher has been sent to to unlock it.

No need to EVER use the Internet with the Kobo, for Annotations or anything else once registered with fake email address. Or you can use a real one. Less bad than giving it to Amazon.