Thanks for everyone’s suggestions!
I think RGT might be my preferred option right now, as I’m still having problems with my heart rate monitor reconnecting to SYSTM after ending a workout and starting another (it seems to reconnect about 20-30% of the time if I do some permutation of disabling/re-enabling Bluetooth and closing and re-opening the app, but not very predictably). Interestingly this doesn’t seem to be a problem with ending and starting a new ride in RGT, only in SYSTM, although I guess that makes sense as they have different codebases.
Ideally it would be great to have the the functionality to automatically load up a cooldown right after a SYSTM workout finishes, but seems like this is a decent option for the time being.