Harming or taking any sentient beings life is a wrong action, an evil action. It causes immense loss of wisdom, perspective, empathy and friendliness of your own mind; and it causes severe suffering to the beings that are subjected to your violent acts.

You are accumulating demerit by continuing these actions, there is truly no action worse than murder. The right time to stop is right now. I hope you stop ignoring the (now) diminished sense of wrongdoing, that made you okay with doing this.

Thunderbird application settings being client side, have a separate sync design, unrelated to thundermail. I don’t remember whether they finished it, but I do remember they were working on a sync feature.

I highly suggest Thundermail (tb.pro) if you wanna switch to a libre email provider. Mozilla hosts stalwart and their own libre mail client for you, along with providing 15 mail aliases and 3 custom domains, for a small price. I have been using it as my daily since past few months. I haven’t found any bugs despite it being in beta.