The driver Polling Interval governs how often all devices are scanned. If a complete scan already takes longer than the setting, reducing the setting cannot make that scan faster. If it finishes sooner, the next scan waits until the interval has elapsed.
The device Request-Frame Interval is the time from sending one request to sending the next. Post-Write Refresh Interval is the wait between completing a write and requesting that value again. The channel timeout governs how long to wait for a response. Check response time, tags and messages first, then adjust parameters individually while observing quality and actual refresh time.