i am not sure, but i think, the Garmin FTP Test is totally wrong and not like the Standard FTP Test Protocols, or?
in the 20min phase, the Garmin Test change the Target of the Power every 4 minutes higher, the first 4 minutes are arround my actual FTP and then Garmin increases the value, after 8 minutes to a value where it's impossible for me, to hold till to 12 minutes, same after the next step, the target is now so high, more ore less 100 Watt over my actual FTP, it's impossible to hold it so long.
Why all other to the FTP testing different, like Zwift, in Zwift you get the message after 10minutes, you have now a average of e.g.210 Watt, try to increase it, so you cqan hold it for the next 10 minutes?
i know, i do cycling for fun and i am near 50 years old, but is this Testing really right?