Vacuum cleaner lost suction power, possible fix?

A few days ago I noticed my beloved and terrifically useful vacuum cleaner lost suction power, so I deep cleaned it. However, it didn’t fix it and now it simply doesn’t pickup anything.
Upon close inspection I noticed that the was a gap between the bottom circular black cover and the garbage reservoir, so it’s not completely sealed and thus not creating vacuum.
I found out that one tooth was broken in the latch and that it was possibly missing a rubber o-ring to close that gap, but i don’t remember seeing it and much less if I lost it.
In that matter I’d need to know if it’s possible to purchase only the parts that are broken or missing, or if my only option is throwing the whole vacuum cleaner to the trash and buy a new one?
Thank you for your help.

Welcome to the forum @mfgilm

The below thread offers a few fixes for the loss of suction. As you identified it’s the missing canister ring.