Earlier quoted context omitted.
I work for an organisation that is at this scale on AWS. Of course, we use Terraform, but the cost explorer and tags and so on are still usable (and useful).
That’s fair, I should have caveated this statement with the fact that I don’t know much about using the modern AWS console. There are likely a few factors at play here, including the fact that Netflix decided to go its own way in this regard ~15y ago. Though I work at a smaller (but still large), newer company now we still also have our own stuff for this.
For we have in the order of 10^6 SNS topics in one account+region pair. In that account, while in that region, the SNS console is entirely frozen. I suspect they're doing some looped pagination polling in the background and fall over on our degenerate use case.
Edit: I can also back up the other parent comment - tagging still works fine (and I know for a fact the stability and scalability of the tag system is taken more seriously than most things within AWS)