I'm a long time (yearly plan) user with a similar experience.

The crux of the issue is that Pinboard's centralized architecture is unsustainable in the long run. It's essentially an on-demand archive.org service with the same ever-increasing storage requirements, which becomes a bigger problem as more users join.

It must be difficult for a one (or two) person team to manage, especially since they also chose to manage their own hardware. I assume this is to avoid cloud storage and hosting costs, and I respect the decision, but this can add a lot of overhead on top of just keeping the software performing optimally.

The sustainable model for this type of service is self-hosted. https://archivebox.io/ seems like a nice solution I've been meaning to try.