1.9.0 0.9.1 v0001.0 Build 240717 rel 77222n

I bought this modem less than 3 months ago. Performance varies between awful and ordinary. My Samsung S22 consistently speed tests at 160-185 Mbps on 4G connection which is throttled to 150 Mbps on the Telstra network. MR500 consistently speed tests using internal speed test at between 30-109 Mbps at same location as phone. This sometimes causes buffering when streaming 4K video. Speed tests over wifi at 3m have never exceeded 70 Mbps.

I've tried rotating the modem, changed from horizontal to vertical, recently updated to latest firmware, manually selected bands instead of auto aggregation. Nothing has made any improvement.

Is there anything I can do to make this modem usable or should I return for refund?