Can I suggest you to give a try to Betterbird (https://www.betterbird.eu/ https://www.betterbird.eu/)? Betterbird is a fine-tuned version of Mozilla Thunderbird

Can I suggest you to give a try to Betterbird (https://www.betterbird.eu/ https://www.betterbird.eu/)? Betterbird is a fine-tuned version of Mozilla Thunderbird, with addition bug Fixes and optimizations.