I have a first world problem of not having a power meter on all my bikes. I could move a power pedal around as I ride them, but I’d be interested to know how much more beneficial power would be to the data, v’s just riding with a HRM, thinking about the fitness curve, and whatever else might be affected.
Intervals.icu will estimate load from HR only activities using one of several algorithms. The default is HRSS from Elevate. I will do the same for activities with power and HR. You can click the load number in the activity summary to see the tpower and HR numbers to get an idea how well it is working for you.