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I do think proton is to some extend better that some of others ( usualy these more local one)... i noticed the initial non-google email provider wich i used to ( seznam.cz) have realy weird isues of antispam , and also sometimes endup mail of x , in wrong mailbox user or so somehow .... and thats is one of biggers local one freemails...... or so
no idea about details of how they run stuff
i still use Thunderbird , as mail client , and yes i know it's probaly minority of people who use emails clients
but i also tryed most of others emails clients , and most close to ideal by functions was i think Blue Mail , didnt like UX much .
