Email is still critical for communicating. Luckily there is a top-tier client for email that is open source: Thunderbird.
Thunderbird is very simple to setup, easily connecting to major email providers or to a personal/business account. It stores your email in a way that is easy to backup. It isn’t particularly flashy, but you want an email client to be functional, not flashy.
FLOSSing for lent 22/40