Are you using Opensearch for logging or site search? $371 seems like a lot for a low traffic site. You can probably reduce the cost to a fraction by doing some research on alternatives
Yeah if your low traffic site doesn't need any crazy compute you can probably run it for $5/mo on any commodity VPS provider like Linode or DigitialOcean
I saw your comment about anvere and looks like you have a background in search/ES? I'd be interested to chat but didn't see a way to contact you!