So a simple remedy for a minor annoyance of scrolling down to access the TRS22 folder seems to made a difference. I reassigned the TRS22 folder (whatever it's called) in the hidden 'Appdata' folder, and merged the contents into a new TRS22 folder with a number prefix to bring it near the top of the documents folder.
I then reassigned the folders in TRS22 content manager, and ran TransDEM with the following UTM export parameters in this image:
8EbThe UTMs seem to render clearly now in the portion on the route covered by them, without any obvious interference. But will they render like this subsequently? Time will have to tell.
As for the inconvenience of the progress bar being visible, this ordeal was enabled by running the 2.6.6.1 update.