As a recent convert from a 2018 GTL to a 2021 GSA TE I can tell you the GSA is light years ahead Audio/BT/NAV wise.
My BMW Navigator VI, bought new with my 2018 GTL has blown up 3 times. I am now on my 4th example. That said the latest one which arrived yesterday is the 'Refresh' version and came in a brand new sealed box with all the extras such as a case etc and required the battery to be fitted. Previous replacements came as a head unit only. Garmin tell me the screen is entirely new, designed and manufactured to cure the ghosting/failure issues that have blighted this very expensive price gouging BMW edition Garmin. We shall see shortly.
Contrary to some here I find the TFT and accompanying APP to be a great success. That said I do have an Android phone with BT 5. I believe the TFT has BT 4.? which helps with transfer rates et al. Yes it does take a moment to connect to the phone and headset from ignition on, but I've got into the habit of switching the ignition on, then my helmet then the gloves and finally, by the time I climb aboard all is connected and ready to go. The sound prompts are clear and the left right distance to go to turn on the TFT is very useful once you have it in your scan. I also use the myroutes.app for route planning. Save the route as a GPX then send it to myself from my laptop to my phone on Whats App for example. When opened on the phone the GPX file is automatically opened in the BMW connect app and you're ready to go. Down route I do the planning on my phone or on my laptop whichever is convenient. Having photos taken on the phone geographically placed on the recorded route is quite the thing and very useful for those "where was that moments'.
Lastly I do not or have not to date connected the Nav 6 voice to my helmet. I'll give that a go with this new version 10 software and see how that goes.
Stay safe out there.
Tony