6wk beginner FTP- handcycle

I’m 59 and use a handcycle (chronic illness that affects legs); I’ve been riding for three years and decided to try the 6wk Beginner FTP builder. I did my ramp test, made the first week fine, but the last part of week two is beyond my ability. I can hold the target power (150-170) for one minute out of three required minutes, etc. The chat keeps saying I should be handling these efforts with some ease, but I can’t get through them without stopping to catch my breath. Is this just me? A handcycle thing? Or…,?