Are you sure you have the Stryd Power data displayed? If two power streams are available in the FIT (Garmin and Stryd for example) you can choose which one to set as default in Intervals. Go to the bottom af the activity page, Actions - Settings
In Power Field, you can check if multiple fields are available and set which one you want as default.
I’m not sure if something is available for speed/temp… from Stryd. I don’t have Stryd. If it comes from another IQ field, you should be able to get that from the Custom Streams. Check if there are multiple speed fields in the FIT and eventualy configure as Custom Stream.
DFA-a1 comes from the AlphaHRV IQ field and is fully integrated in Intervals. If the data is available in the FIT, just activate the dfa chart(s).
There’s a big thread here on the forum regarding all functions of AlphaHRV and the dev regularly is on the forum.