Thunderbird should work: https://www.xfinity.com/support/articles/setting-up-thunderbird
The others said it. Thunderbird
Thunderbird, which several other on this thread have recommended, is solid and reliable. I have been using Tbird literally for years and never had a single problem with it.
Couple of links to check:
https://support.mozilla.org/en-US/kb/installing-thunderbird-linux
https://www.thunderbird.net/en-US/download/
Thunderbird has an option to download complete messages.