As far as i know, the BLE valid Tx power values which can be configured range from: -20, -16, -12, -8, -4, 0, 3, 4 dBm, so you already have the highest one configured.
Try assigning the iot radio-profile globally instead of per-AP, to check if that solves the case.
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Shpat | ACEP | ACMP | ACCP | ACDP
Just an Aruba enthusiast and contributor by cases
If you find my comment helpful, KUDOS are appreciated.
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