Unable to edit or add to PIP application form?

I have COPD (bullous emphysema - luckily not severe at present) and a long history of Depression and Generalised Anxiety Disorder. I am 99.9% sure I am neurodiverse (ADD and/or ASD) but not yet officially diagnosed. I had many years of unemployment due to mental health issues, and many run-ins with the DWP, including winning a tribunal after they tried to deny me the Limited Capacity for Work element of UC (I spotted that they had 'omitted' certain evidence from their submission to the tribunal!). At the moment being driven mad by the 'Beta' version of the PIP application form (see also other threads) which I notice has been 'in development' since at least 2022 and which apparently won't let me edit or add to any answers I've already given after I save the form - which seems to be a problem several people on here have had, though others say they can go back & edit. Blowed if I can see how, though. Thoughts?