Im the sponsor and applicant is outside Canada.
Then if I'm not mistaken one or two comments above may have misunderstood on basis that understood you were the applicant and not the sponsor.
As PR-sponsor you are expected to reside in Canada. Short visits abroad have generally been considered normal. I think it's fair to say that "visits" abroad have generally (historically) been interpreted to mean less than one month abroad, continuous, the shorter the better, 2-3 weeks perhaps 'normal'. This is from reports here.
If IRCC decides you are not residing in Canada, they can cancel the app, on basis you are not resident.
There have been conflicting reports/comments here - e.g. from call centre employees, social media "comments" - that it's "okay" to travel abroad for longer. These second-hand reports are not consistent and do not provide specific criteria.
Those statements from a call centre employee cannot be relied upon. They are not a written permission, and there is no way to get a written permission.
As far as I'm aware, there is no published guideline that says longer is okay, or what recourse might be, or circumstances (covid-related or otherwise) that might serve to "exempt" a PR-sponsor who leaves for longer periods.
So unfortunately - again, as far as I can tell - there is no way to give solid advice.
As far as notifying IRCC - again, no solid way to say. It might cause them to look at your file. It may give them enough info to (compassionately) decide to ignore the issue.
One warning: do not assume that because you have not notified them, that they cannot find out if they wish to, or that they will not receive this info automatically (I don't think anyone knows). Assume they have access to border crossing info, whether by plane or otherwise.
Note: I've summarised what seems to be experiences from others here, and publicly-available info about the rules for PR-sponsors. I've purposefully avoided giving recommendations.
Because as far as I can tell no-one knows (I'm open to corrections), and believe no-one can give you solid answers or advice on the main parts of your question.
Unfortunately that means it's up to you to decide and take the risk. Personally I don't think it's even possible to even guess how big the risk is.
Probably the only relatively clear and positive thing that can be said is that if your current application should be cancelled for this reason, it should not negatively affect re-applying to sponsor your spouse (when your the PR are resident in Canada). Obviously this would still mean more delays.