Honestly, I don't want that lifestyle. I live in the burbs with a big house and yard. We travel plenty and go to places that are dense/walkable but I love coming back home to my carbrained neighborhood with an HOA.
Everything's connected to the internet, what the OP was talking about was attack vectors and since Transmit is a local app it really isn't one unless your whole machine is compromised, which in that case you're screwed.
They've been shipping features somewhat regularly. One I really like (but was unfortunately gated behind a $10 price bump) was being able to ask AI to find an email "where's that email about blah" or to have it summarize a long email chain "hey what am I supposed to be doing here"