As of the last official statement (from memory) TR AI FTP Detection needs a minimum of 12 completed rides/workouts imported in your TR calendar. There was some confusion as to whether that must be TR or other rides, but AFAIK it includes ALL ride types, not just TR ones at this time for the minimum of 12.
Other than that restriction, TR AIFTPD is supposed to use ALL workouts with power data as part of the Detection background data. All that said, if you meet the requirements above, using AIFTPD is what I’d suggest.
Essentially, look for the AIFTPD option in your Career page on the Ramp Test, and if the option is available, you are good to use it.