Approved today! Thanks to everyone who contributed to this thread - it has been very comforting during this wait.
Here's my timeline:
June 20, 2024: Applied for SP extensions for myself and my primary school child
Dec 3, 2024: Submitted a webform
Dec 19, 2024: Received response to webform saying basically nothing
Jan 6, 2025: My application status was updated to under review on the IRCC webpage when I checked it, but I never got an email notice about that.
Jan 9, 2025: I received email notices that my application status has been updated and then a notice of approval about 15 minutes later.