In several jurisdictions (certainly the USA and Australia, Germany too) Amazon Kindle customers are told that by February 25th the ability to download books to your computer (for later transfer to your device over USB) will be disabled. I haven’t seen it in my Dutch Amazon store yet. That makes me wonder if it is a phased roll-out. This won’t prevent you from reading your e-books in any way, but will prevent you from storing them in useful formats outside of the Amazon silo (so that Amazon no longer can remove them at will).
I realise my steps to move all my Amazon bought e-books to an environment I control have been timely (yet, also late by several years one might say).
Within the next 10 days downloading Kindle book files and using Epubor to move them into your Calibre library should likely be a priority if you care about long term autonomy over your e-readings. Enshittification avoidance is a civic duty I’d say.
Where enshittification happens it must be made to hurt the companies choosing it. Like by no longer sending money their way. So this step just makes avoiding Amazon purchases easier to keep up for me.