I've been using Thunderbird on my PC for many years. That will be an easy transition. I also refuse to leave my emails on whatever server I am linked to. Those that are saved are downloaded to my PC, and those local files are backed up regularly to three other drives (yeah, I'm that paranoid).
I can’t convince my wife to use a client like TBird. She insists on using our ISP’s interface as her email app. Oh well.