I think the current Strength TSS score is still lacking. I think at the bare minimum, because it is far from “ideal,” the strength TSS should be based on volume and/or some % of estimated 1RM for each lift.

That way it would be pretty easy to calculate a sTSS score so long as TP knows the sets, reps, and weight for each lift in the workout.

For volume that would be very easy to add up the weight. And for % of 1RM (which is better in my opinion for sTSS) There are pretty easy formulas to estimate 1RM based on whatever workout someone is doing and TP should be able to calculate and define TSS with the same workout data.

That way it will work whether it was done in the strength builder, or through Garmin strength builder, or any 3rd party strength app (like Hevy), since all the required data is automatically defined in the workout activity log