One way to do this:
1) go to account settings
2) go to layout/QuickViews
3) choose the workout type from the dropdown (e.g. run, swim, bike…)
4) remove pace from the selection of metric “In Use – Planned/Completed”
This should mean all the workouts of that type default to hrTSS and not rTSS.
If you do want rTSS ordinarily, just manually change to hrTSS.