I'll address the point you raised canasta without pouring the scorn on you taht the usual suspect do to anyone who is cautious about covid and wants to avoid putting themself or others who may be vulnerable at risk .
I think its partly that people have been stockpiling them so stock has ran low, and also because they dont want to give away all stock now when some may just get wasted, gather dust or thrown away.... better that people only take them as there needed
I got tested last week canasta- rang for a PCR and got a booking for in less than an hour at a drive through/walk through only 15mins away. The PCR was free, There was an option to have a LTF sent to me but PCR were quicker
you dont have to test in the last days. i think the current guidance is to isolate for 10 days. if you had tests, and you wanted to follow guidelines you could test on day 6and7 and finish isolation early if they were neg