On the other hand, matrix stores your profile info, group membership, and ongoing conversation metadata in plaintext, some of them replicated across homeservers. In addition to metadata that matrix doesn't encrypt, they also do not encrypt some actual data like emoji reactions.
Edit: clarified that conversations are not in plaintext. My wording what confusing as hell sorry.
I found a solution by running
flatpak run --command=/app/bin/thunderbird org.mozilla.Thunderbird