For years I have had no coverage in Portarlington on the esplanade despite the map showing good coverage. Torquay is now no better, as little as no data coming through on data only sim during the day and evening, 25mbps late evening and overnite. My partner getting 25-35 on Telstra 4g.
Also, despite lots of buffering and dropouts, I show as using 10gb last night but couldn’t watch anything cause of the extreme buffering.
That does sound quite frustrating.
Have you contacted Optus directly to get them to check out the location thoroughly and walk through some troubleshooting? (which is all we can really advise here on our public forum)