What's the latest advice on IRCC website?
As far as I know they extended the submission deadline from 60 to 90 days to allow extra time to gather documents with the pandemic ongoing. And if you are affected by the pandemic and still not able to provide the documents close to the deadline I believe they'll extend the submission period if you contact them via the webform to advise them.
Check if there are other allowances though. I'd expect they would want the work reference included. Medical you can probably go without initially, as this is not always necessary upfront, and so many Panel Physicians are not open atm.