This seems a case in which AWS Support should be able to help you.
Your best next steps would be to open a Support case, in case you have not yet a Support subscription, consider to upgrade to Developer Support or Business support depending on the urgency of your case.
Without looking at the internal logs or having more detailed information on the situation it is not possible to provide guidance, sorry.
Is it really supported to use alerting on "AWS Elasticsearch"?asked 3 years ago
Instance stuck on stoppingasked a year ago
Impact to AWS Elasticsearch on the licensing change of Elasticsearch(elastic.co)Accepted Answerasked 2 years ago
Cache cluster stuck on taking backup and deleteasked 3 years ago
One of my instances is stuck at login screen (viewed on system logs) after restarting or stop then start! Can't SSH to it!asked 8 months ago
AWS ElasticSearch Stuck Upgrade processing after 3.5 hoursasked 2 years ago
ElasticSearch service stuck on "being deleted"asked 8 months ago
openSearch cannot be deleted as it stuck in "Being Deleted"asked 9 months ago
Amplify ElasticSearch Domain stuck in "Upgrading" stateasked 3 months ago
ElasticSearch version change gets stuck in Amazon OpenSearch Serviceasked 4 months ago