I’ve actually had the same issue with quotas seeing a very chaotic behavior and getting lockouts for multiple days while using Opus/Sonnet, then I’ve seen this reply from @Bailee and went through those links. I don’t know if it’s a coincidence, but after I followed the recommendations in those linked posts, deleted antigravity-panel and other extension for auto-accept, and actually implemented own quota monitor PS script plus own auto-accept extension with Gemini 3 (these quotas are the most generous), I have my 5-hour Claude Opus/Sonnet 4.6 quota reset again and they are back to their adequate capacity (like implementing medium backend feature with multiple phases within single 5-hour quota limit). Either there is some issue with those extensions (either malware or maybe Antigravity identifies them and “punishes” users for using them), or Google has increased the Claude quotas exactly around the same time I removed those extensions.
UPDATE: After fully using 5-hourly quota with Claude only twice within 24 hours, I can see again the lockout for the whole week. It means that the mentioned by me extensions are not the root cause and Google further keeps very low quotas on Claude models for PRO users.