Combining Apple Fitness+ workout with outdoor run on Watch

Hi - I'm trying to combine my usual outdoor run with strength training workouts from Apple Fitness+. I know I can log these separately but there's a reason I need to get them to count as one! So far I can see two options but neither work for me:

1. Combine workouts in Apple Watch - start the run, then tap new and add a strength workout. The problem is I can't select an apple fitness+ workout, only a generic strength one. If I try to start an apple fitness+ workout on my phone it tells me to end the other workout (so won't record as one whole workout).
2. Use stacks in Apple fitness - however there isn't an option to add my own outdoor run. I can only select a treadmill run. There are audio guided runs...(I don't really want the audio but wouldn't have to listen)....but I don't think you can stack them anyway!

Sorry if I'm just missing something - any advice or solutions would be great :)