Please see https://www.amazon.com/kindle-dbs/arp/B0C9PRPV28 for information regarding application end of life.
kindle is built for Intel macOS and so requires Rosetta 2 to be installed.
You can install Rosetta 2 with:
softwareupdate --install-rosetta --agree-to-license
Note that it is very difficult to remove Rosetta 2 once it is installed.
