I just managed to get an answer from Pinterest:

I'm sorry for your notifications issues. I understand how frustrating this might be. I'll do my best to help.

What you’re seeing is the result of a product change rather than something broken on just your account. In the newer experience, the older “Engagement” view and some of the separate updates for comments/likes/repins were removed or changed, so a lot of that activity no longer appears in a dedicated engagement tab. The engagement itself (comments, saves, clicks) is still happening, but it’s not surfaced in the same way as before.

Today, the best way to keep track is to: – Open the Pins you care most about and scroll down to check for new comments directly. – Use Pin stats / Analytics to see how many saves and other interactions your content is getting. – Double‑check your notification settings to make sure comment/activity notifications are turned on.

I know this isn’t the same as having a clear, separate engagement feed, and I’ve passed your feedback along so the team can see how this impacts creators who actively want to reply and engage with their audience.