Wow this is so pessimistic!
First, if your case is in process, I think you're far from being invited to the ceremony, you have to switch to "decision made", and then wait a few more months. Secondly, your numbers are wrong, people who recently became citizens got their certificates in 3-4 weeks only, and in case you need to travel, you can still ask for an emergency passport. And if you don't plan to travel in 2021, then what's the point?
It's better to become a citizen asap, than to have to renew your expired PR card...
In my case, I know I won't travel abroad in 2021 because that covid situation will probably mess everything up until September or October... So it won't be a big deal for me if I have no PR card and no canadian passport for 2 or 3 months