brent T-Bird and other mail aggregates always seem middlemen between you and your account,
A webmail client is just another client. Just like Thunderbird, Claws etc. The only difference is that Thunderbird is a local client, and the web client is on a server. Both are just interfaces to view and manage your email. There's nothing wrong with preferring one or the other.
The only way to not have a "middleman" is to read the text from IMAP directly on the server without any client at all. That's not feasible. Just want to clarify things.