Thank you @kgalusha - your comment led me to find this workaround in my case.
I was also using Edge as my browser - TT Desktop would invoke a new Edge window to try to connect to E*Trade. When that process seemingly completed, there was no pop-up to accept the transfer, nor was there any indication that a pop-up was blocked. Which I think is what led so many of us into the loop and going back to the "Continue" button in TT, which didn't do anything except frustrate ppl by repeating the process.
I changed my default settings to use Chrome for all browser content and tried it again. Now, TT opens a Chrome window *(rather than an Edge window) to connect to E*Trade and after credentials are processed, data-xferred/etc, a pop-up appears that one has to accept to complete the transfer.
I did nothing that I know of to enable a setting in Edge, nor disable one in Chrome, so that this behavior was the case - but at least for me, setting Win11 to use Chrome for all Web/HTTP/HTTPS actions, "solved" the issue.
Thanks for the hint!
