I am using a Garmin 1030 Plus with a Polar Verity. The reason for calling that out is there appears to be some difference between various Garmin computer versions and how they calculate FTP. I am also over 50 which I believe has an impact on my ability to complete a ramp test.
When I do ramp tests I always seem to struggle at the end of them or I don’t enjoy pain and quit early 
Today was ramp test day and TR came back and told me I had an FTP of 214W but the Garmin came back with an FTP of 247W.
I use the FTP from the Garmin and have been pretty much completing all the TR workouts through the last two base cycles. With gradual increases in TR levels over the course of the blocks.
One issue I do have is that if I change my FTP manually all TR adaptive training levels get reset to one if I let it. This I find quite frustrating and end up ignoring the Adaptive Training level changes for the first week whilst it adjusts itself back to the levels I had been training at.