My pleasure!
Even if we inform them that we have decided not to travel prior to the expiry of CoPR - but later change our mind, IRCC is clear that we can travel anytime we choose to do so, as long as the CoPR is still valid. No explanation or prior information is needed for changing our mind and land.
Currently and understandably MOST if not all responses are rather generic, with same or similar message from IRCC, so nothing to worry there. I do think IRCC is fairly alright in responding to questions - afterall it is better to ask the question if we have them. I would do the same!
Once the CoPR expires, whether or not medicals are re-requested shall remain unknown and most likely vary case to case. This is simply my guess - have not seen any instructions related to circumstances under which re-medicals will be sought by IRCC.
There is no expectation of anything additional to re-medicals, PRV stamping et al.
For what its worth, I personally would try to travel before CoPR expires. Obviously, this will be different for each individuals' circumstances. Go with your gut feel! Be safe and informed!
I wish you well!