" <...> [Thunderbird] consider it a "least awful" choice. It's less complicated, opinionated, and buggy that Outlook. It's cross-platform unlike some of the other top-tier options. <...>"

Absolutely correct, it's why we have to put up a strong clear-cut case now to ensure the developers know exactly what we users want. To do just that will, on occasions, require us to be very specific.

We should not be the slightest bit shy about complaining.